android - 如何从 java 类文件中更改布局中 TextView 的值？

Question

布局文件-listitem_discuss.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >


<LinearLayout
    android:id="@+id/wrapper"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">"

    <TextView
        android:id="@+id/comment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dip"
        android:layout_marginRight="20dip"
        android:layout_marginTop="5dip"
        android:layout_marginBottom="5dip"
        android:background="@drawable/bubble_yellow"
        android:paddingLeft="10dip"
        android:text="Hello bubbles!"
        android:textColor="@android:color/primary_text_light" />

    <TextView 
        android:id="@+id/tstextbox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dip"
        android:layout_marginRight="20dip"
        android:layout_marginBottom="5dip"
        android:text="TimeStamp"/>
</LinearLayout>

</LinearLayout>

布局文件-activity_discuss.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<ImageView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:src="@drawable/bg" 
    android:scaleType="matrix"
    />


<ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="115dp"
    android:layout_marginBottom="10dp"
    android:layout_above="@+id/form"
    android:layout_alignParentTop="true" >
</ListView>

<RelativeLayout
    android:id="@+id/form"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:ems="10"
        android:hint="Talk to me"
        android:inputType="text" />
</RelativeLayout>

</RelativeLayout>

Java 类文件 * Page1.java *

public class Page1 extends Activity {
private com.anr.aifv1.DiscussArrayAdapter adapter;
private ListView lv;
private EditText editText1;
@Override
protected void onCreate(Bundle savedInstanceState) {

//Remove title bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);

//Remove notification bar
//this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_discuss);
    lv = (ListView) findViewById(R.id.listView1);
adapter = new DiscussArrayAdapter(getApplicationContext(),R.layout.listitem_discuss);
lv.setAdapter(adapter);
editText1 = (EditText) findViewById(R.id.editText1);
editText1.setOnKeyListener(new OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
// If the event is a key-down event on the "enter" button
if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
// Perform action on key press
adapter.add(new OneComment(false, editText1.getText().toString()));

adapter.add(new OneComment(true, "Thank you"));
    editText1.setText("");
//tstextboxjv.setText("Sample");
return true;
         }
return false;
        }
    });
}
}

讨论ArrayAdapter.java

package com.anr.aifv1;

import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
    import android.widget.TextView;

public class DiscussArrayAdapter extends ArrayAdapter<OneComment> {


private TextView countryName;
private List<OneComment> countries = new ArrayList<OneComment>();
private LinearLayout wrapper;

@Override
public void add(OneComment object) {
    countries.add(object);
    super.add(object);
}

public DiscussArrayAdapter(Context context, int textViewResourceId) {
    super(context, textViewResourceId);
}

public int getCount() {
    return this.countries.size();
}

public OneComment getItem(int index) {
    return this.countries.get(index);
}

public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    if (row == null) {
        LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        row = inflater.inflate(R.layout.listitem_discuss, parent, false);
    }

    wrapper = (LinearLayout) row.findViewById(R.id.wrapper);

    OneComment coment = getItem(position);

    countryName = (TextView) row.findViewById(R.id.comment);


    countryName.setText(coment.comment);

    countryName.setBackgroundResource(coment.left ? R.drawable.bubble_yellow : R.drawable.bubble_green);
    wrapper.setGravity(coment.left ? Gravity.LEFT : Gravity.RIGHT);

    return row;
}

public Bitmap decodeToBitmap(byte[] decodedByte) {
    return BitmapFactory.decodeByteArray(decodedByte, 0, decodedByte.length);
}

}

OneComment.java

package com.anr.aifv1;

import java.util.Calendar;

import android.widget.TextView;

public class OneComment {
public boolean left;
public String comment;

public OneComment(boolean left, String comment) {
    super();

    this.left = left;
    this.comment = comment;
}



}

这运行良好。但是当注释语句“tstextboxjv.setText("Sample");” 未注释，该应用程序。崩溃。

我的目标是使用 TextView 来显示聊天气泡的时间戳。

Logcat 堆栈跟踪

04-14 13:11:48.094: D/AndroidRuntime(940): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<<
04-14 13:11:48.094: D/AndroidRuntime(940): CheckJNI is ON
04-14 13:11:48.144: D/dalvikvm(940): Trying to load lib libjavacore.so 0x0
04-14 13:11:48.154: D/dalvikvm(940): Added shared lib libjavacore.so 0x0
04-14 13:11:48.194: D/dalvikvm(940): Trying to load lib libnativehelper.so 0x0
04-14 13:11:48.204: D/dalvikvm(940): Added shared lib libnativehelper.so 0x0
04-14 13:11:48.934: D/AndroidRuntime(940): Calling main entry com.android.commands.pm.Pm
04-14 13:11:48.994: D/AndroidRuntime(940): Shutting down VM
04-14 13:11:49.025: D/dalvikvm(940): GC_CONCURRENT freed 102K, 78% free 466K/2048K, paused 6ms+9ms, total 32ms
04-14 13:11:49.025: D/jdwp(940): Got wake-up signal, bailing out of select
04-14 13:11:49.025: D/dalvikvm(940): Debugger has detached; object registry had 1 entries
04-14 13:11:49.664: D/AndroidRuntime(954): >>>>>> AndroidRuntime START com.android.internal.os.RuntimeInit <<<<<<
04-14 13:11:49.664: D/AndroidRuntime(954): CheckJNI is ON
04-14 13:11:49.744: D/dalvikvm(954): Trying to load lib libjavacore.so 0x0
04-14 13:11:49.744: D/dalvikvm(954): Added shared lib libjavacore.so 0x0
04-14 13:11:49.785: D/dalvikvm(954): Trying to load lib libnativehelper.so 0x0
04-14 13:11:49.794: D/dalvikvm(954): Added shared lib libnativehelper.so 0x0
04-14 13:11:50.554: D/AndroidRuntime(954): Calling main entry com.android.commands.am.Am
04-14 13:11:50.604: I/ActivityManager(174): START {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.anr.aifv1/.Page1 u=0} from pid 954
04-14 13:11:50.634: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.634: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.634: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.634: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.634: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.634: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.644: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.644: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.644: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.644: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:11:50.644: W/WindowManager(174): Failure taking screenshot for (266x425) to layer 21005
04-14 13:11:50.665: D/AndroidRuntime(954): Shutting down VM
04-14 13:11:50.734: I/AndroidRuntime(954): NOTE: attach of thread 'Binder_4' failed
04-14 13:11:50.744: D/dalvikvm(966): Not late-enabling CheckJNI (already on)
04-14 13:11:50.764: I/ActivityManager(174): Start proc com.anr.aifv1 for activity com.anr.aifv1/.Page1: pid=966 uid=10043 gids={1028}
04-14 13:11:50.774: D/dalvikvm(954): GC_CONCURRENT freed 102K, 77% free 489K/2048K, paused 30ms+1ms, total 99ms
04-14 13:11:50.774: D/jdwp(954): Got wake-up signal, bailing out of select
04-14 13:11:50.784: D/dalvikvm(954): Debugger has detached; object registry had 1 entries
04-14 13:11:51.294: E/Trace(966): error opening trace file: No such file or directory (2)
04-14 13:11:52.154: D/dalvikvm(966): GC_FOR_ALLOC freed 60K, 5% free 7252K/7555K, paused 52ms, total 54ms
04-14 13:11:52.174: I/dalvikvm-heap(966): Grow heap (frag case) to 9.518MB for 2457616-byte allocation
04-14 13:11:52.424: D/dalvikvm(966): GC_CONCURRENT freed <1K, 4% free 9652K/9991K, paused 74ms+13ms, total 247ms
04-14 13:11:52.618: D/dalvikvm(966): GC_FOR_ALLOC freed 0K, 4% free 9652K/9991K, paused 35ms, total 35ms
04-14 13:11:52.684: I/dalvikvm-heap(966): Grow heap (frag case) to 13.672MB for 4356164-byte allocation
04-14 13:11:52.897: D/dalvikvm(966): GC_CONCURRENT freed 0K, 3% free 13906K/14279K, paused 74ms+16ms, total 216ms
04-14 13:11:53.385: D/gralloc_goldfish(966): Emulator without GPU emulation detected.
04-14 13:11:53.526: I/ActivityManager(174): Displayed com.anr.aifv1/.Page1: +2s816ms
04-14 13:11:54.454: I/Choreographer(333): Skipped 64 frames!  The application may be doing too much work on its main thread.
04-14 13:12:06.664: E/PowerManagerService(174): Excessive delay setting brightness: 126ms, mask=2
04-14 13:12:07.084: E/PowerManagerService(174): Excessive delay setting brightness: 140ms, mask=2
04-14 13:12:10.284: D/AndroidRuntime(966): Shutting down VM
04-14 13:12:10.334: W/dalvikvm(966): threadid=1: thread exiting with uncaught exception (group=0x2bc9a300)
04-14 13:12:10.508: E/AndroidRuntime(966): FATAL EXCEPTION: main
04-14 13:12:10.508: E/AndroidRuntime(966): java.lang.NullPointerException
04-14 13:12:10.508: E/AndroidRuntime(966):  at com.anr.aifv1.Page1$1.onKey(Page1.java:53)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.View.dispatchKeyEvent(View.java:7081)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1358)
04-14 13:12:10.508: E/AndroidRuntime(966):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1892)
04-14 13:12:10.508: E/AndroidRuntime(966):  at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1369)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.app.Activity.dispatchKeyEvent(Activity.java:2356)
04-14 13:12:10.508: E/AndroidRuntime(966):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1819)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewRootImpl.deliverKeyEventPostIme(ViewRootImpl.java:3577)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewRootImpl.deliverKeyEvent(ViewRootImpl.java:3533)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3115)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4155)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4134)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:2932)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.os.Looper.loop(Looper.java:137)
04-14 13:12:10.508: E/AndroidRuntime(966):  at android.app.ActivityThread.main(ActivityThread.java:4745)
04-14 13:12:10.508: E/AndroidRuntime(966):  at java.lang.reflect.Method.invokeNative(Native Method)
04-14 13:12:10.508: E/AndroidRuntime(966):  at java.lang.reflect.Method.invoke(Method.java:511)
04-14 13:12:10.508: E/AndroidRuntime(966):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
04-14 13:12:10.508: E/AndroidRuntime(966):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-14 13:12:10.508: E/AndroidRuntime(966):  at dalvik.system.NativeStart.main(Native Method)
04-14 13:12:10.606: W/ActivityManager(174):   Force finishing activity com.anr.aifv1/.Page1
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: E/libEGL(35): called unimplemented OpenGL ES API
04-14 13:12:10.614: W/WindowManager(174): Failure taking screenshot for (266x425) to layer 21015
04-14 13:12:10.634: I/Process(966): Sending signal. PID: 966 SIG: 9
04-14 13:12:10.714: W/InputDispatcher(174): channel '2c56a158 com.anr.aifv1/com.anr.aifv1.Page1 (server)' ~ Consumer closed input channel or an error occurred.  events=0x9
04-14 13:12:10.714: E/InputDispatcher(174): channel '2c56a158 com.anr.aifv1/com.anr.aifv1.Page1 (server)' ~ Channel is unrecoverably broken and will be disposed!
04-14 13:12:10.745: I/WindowState(174): WIN DEATH: Window{2c56a158 com.anr.aifv1/com.anr.aifv1.Page1 paused=true}
04-14 13:12:10.745: I/ActivityManager(174): Process com.anr.aifv1 (pid 966) has died.
04-14 13:12:10.754: W/InputDispatcher(174): Attempted to unregister already unregistered input channel '2c56a158 com.anr.aifv1/com.anr.aifv1.Page1 (server)'
04-14 13:12:10.784: I/WindowManager(174): WINDOW DIED Window{2c56a158 com.anr.aifv1/com.anr.aifv1.Page1 paused=true}
04-14 13:12:10.914: I/Choreographer(333): Skipped 54 frames!  The application may be doing too much work on its main thread.
04-14 13:12:11.037: W/InputMethodManagerService(174): Got RemoteException sending setActive(false) notification to pid 966 uid 10043
04-14 13:12:11.454: I/Choreographer(333): Skipped 50 frames!  The application may be doing too much work on its main thread.
04-14 13:12:11.464: D/dalvikvm(174): GC_CONCURRENT freed 322K, 20% free 9459K/11783K, paused 75ms+39ms, total 774ms
04-14 13:12:12.124: I/Choreographer(333): Skipped 49 frames!  The application may be doing too much work on its main thread.

编辑

 public class Page1 extends Activity {
private com.anr.aifv1.DiscussArrayAdapter adapter;
private ListView lv;
private EditText editText1;
private TextView tstextboxjv;
@Override
protected void onCreate(Bundle savedInstanceState) {

//Remove title bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);

//Remove notification bar
//this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_discuss);
    lv = (ListView) findViewById(R.id.listView1);
adapter = new DiscussArrayAdapter(getApplicationContext(),R.layout.listitem_discuss);
lv.setAdapter(adapter);
editText1 = (EditText) findViewById(R.id.editText1);
tstextboxjv = (TextView) findViewById(R.id.tstextbox);
editText1.setOnKeyListener(new OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
// If the event is a key-down event on the "enter" button
if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
// Perform action on key press
adapter.add(new OneComment(false, editText1.getText().toString()));

adapter.add(new OneComment(true, "Thank you"));
    editText1.setText("");
tstextboxjv.setText("Sample");
return true;
         }
return false;
        }
    });
}
  }

score 3 · Accepted Answer

You need to find the id of your textview and then set text in textview.

All your resources like string, drawables , your views like textview will have a entry in R.java. So you need to find the id. R.id.tstextbox which is an int value. You add textview to you xml layout and save an entry is automatically made in R.java. R.java is auto generated.

In your R.java you will be having an entry for textview as

      public static final int tstextbox=0x7f070001;
      // the value may be different
      // will look something similar to above.

Then you can set the text in textview in your activity class by finding the textview id.

    <TextView 
    android:id="@+id/tstextbox" // id of textview
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="20dip"
    android:layout_marginRight="20dip"
    android:layout_marginBottom="5dip"
    android:text="TimeStamp"/>

In your activtiy onCreate()

      TextView tv=(TextView) findViewById(R.id.tstextbox);
      tv.setText("sample");

Edit:

I tried the below works fine on my device

    et.setOnKeyListener(new OnKeyListener() {
    public boolean onKey(View v, int keyCode, KeyEvent event) {
    // If the event is a key-down event on the "enter" button
    if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
    // Perform action on key press
     et.setText("");
    _tv.setText("Sample");
    return true;
             }
    return false;
            }

Also if you are adding new data to your listview, you should call notifyDataSetChanged() on your adapter to refresh your listview.

Edit 2 :

activity_main.xml

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context=".MainActivity" >

 <TextView
    android:id="@+id/tv"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:layout_marginTop="20dp"
    android:text="Blank text" />


 <EditText
    android:id="@+id/ed"
    android:layout_width="fill_parent"
    android:layout_height="40dp"
    android:layout_marginTop="40dp" />
 </LinearLayout>

Then in my MainActivity

 setContentView(R.layout.activity_main);
 _tv = (TextView) findViewById( R.id.tv );
 et = (EditText) findViewById(R.id.ed);
 et.setOnKeyListener(new OnKeyListener() {
    public boolean onKey(View v, int keyCode, KeyEvent event) {
    // If the event is a key-down event on the "enter" button
    if ((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER)) {
    // Perform action on key press

     et.setText("");
    _tv.setText("Sample");
    return true;
             }
    return false;
            }

Your TextView and EditText should be in the same layout xml file ie activity_discuss.

Then you can get the ids of the same and do the above.

If you need to set text of textview in another layout, check the link below

Transfer data between EditText and Text View

score 0 · Accepted Answer

1.在java文件中定义TextView的布局文件

setContentView(R.layout.activity);

2.定义一个变量链接到TextView

private TextView variable_name;

3. 将变量链接到视图

variable_name = (TextView) findViewById (R.id.TextView_name);

4.设置文字

variable_name.setText("Sample_Text");

android - 如何从 java 类文件中更改布局中 TextView 的值？

2 回答 2

Related

Reference