java - 我使用多个 OnClickListeners 得到致命异常

Question

主要的事情发生在 FATAL EXECEPTION 我的应用程序不启动并且错误来了不幸地停止了它一直在尝试切换案例，否则如果错误仍然继续，应用程序继续崩溃谷歌搜索并搜索堆栈流不同的用户在堆栈流中面临这个错误仍然是错误即使在尝试使用单个 if 和单个 onclicklistener 应用程序设法运行但不使用多个 onlicklistener 的解决方案后继续我是否有不同的方式来运行多个 onclick 侦听器应用程序请帮助我

这是 MainActivity.java

package com.example.cricscore;

import android.app.Activity; 
import android.os.Bundle; 
import android.util.Log;
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.TextView; 

public class MainActivity extends Activity { 

// Private member field to keep track of the count 
private int mCount = 0; 
private static final String TAG = "MainActivity"; 


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 


    Button buttonA = (Button) findViewById(R.id.button1);    
    buttonA.setOnClickListener((OnClickListener) this);
    Button buttonB = (Button) findViewById(R.id.button2); 
    buttonB.setOnClickListener((OnClickListener) this);
 }

   public void onClick(View v) {
       try {
        switch (v.getId()) {
           case R.id.button1: 
               mCount++; 
               final TextView countTextView = (TextView) findViewById(R.id.textView1);
               countTextView.setText(""+ mCount); 
            break;
           case R.id.button2:
               mCount= mCount+2 ; 
               final TextView countTextView1 = (TextView) findViewById(R.id.textView1);
               countTextView1.setText(""+ mCount);
            break;


        }
       }
       catch(Throwable t) {
           Log.e(TAG, t.getMessage(), t);

       }

   }
 }

而 Activity_main.xml 是

<RelativeLayout 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"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView
    android:id="@+id/textView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignRight="@+id/button2"
    android:layout_below="@+id/textView1"
    android:text="Runs" />

<TextView
    android:id="@+id/textView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/textView3"
    android:layout_alignBottom="@+id/textView3"
    android:layout_alignRight="@+id/textView2"
    android:layout_marginRight="19dp"
    android:text="Wickets" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/textView4"
    android:layout_alignParentRight="true"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<Button
    android:id="@+id/button1"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/textView3"
    android:text="1" />

<Button
    android:id="@+id/button2"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/button1"
    android:layout_alignBottom="@+id/button1"
    android:layout_toRightOf="@+id/button1"
    android:text="2" />

<Button
    android:id="@+id/button4"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/button1"
    android:text="6" />

<Button
    android:id="@+id/button6"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button5"
    android:layout_alignRight="@+id/textView4"
    android:text="Wicket" />

<Button
    android:id="@+id/button7"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/button8"
    android:layout_alignBottom="@+id/button8"
    android:layout_alignLeft="@+id/button5"
    android:text="Balls" />

<Button
    android:id="@+id/button3"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/textView3"
    android:layout_toRightOf="@+id/button7"
    android:text="4" />

<Button
    android:id="@+id/button8"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_marginBottom="44dp"
    android:layout_toLeftOf="@+id/textView2"
    android:text="Button" />

<Button
    android:id="@+id/button5"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/button4"
    android:layout_alignBottom="@+id/button4"
    android:layout_toLeftOf="@+id/textView7"
    android:text="No/Wide" />

<TextView
    android:id="@+id/textView6"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/textView7"
    android:layout_alignBottom="@+id/textView7"
    android:layout_alignRight="@+id/button5"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView
    android:id="@+id/textView7"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button8"
    android:layout_toLeftOf="@+id/textView4"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

</RelativeLayout>

日志猫

03-18 14:09:37.717: E/AndroidRuntime(360): FATAL EXCEPTION: main
03-18 14:09:37.717: E/AndroidRuntime(360): java.lang.RuntimeException: Unable to start      
    activity
  ComponentInfo{com.example.abc/com.example.abc.MainActivity}:  java.lang.ClassCastException:    
  com.example.abc.MainActivity
  03-18 14:09:37.717: E/AndroidRuntime(360):    at     
  android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at   
  android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:1663)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at android.app.ActivityThread.access$1500
  (ActivityThread.java:117)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at android.app.ActivityThread$H.handleMessage 
  (ActivityThread.java:931)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at android.os.Handler.dispatchMessage 
  (Handler.java:99)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at android.os.Looper.loop(Looper.java:123)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at android.app.ActivityThread.main 
  (ActivityThread.java:3683)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at java.lang.reflect.Method.invokeNative(Native  
  Method)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at java.lang.reflect.Method.invoke 
  (Method.java:507)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at  
  com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at com.android.internal.os.ZygoteInit.main 
  (ZygoteInit.java:597)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at dalvik.system.NativeStart.main(Native Method)
  03-18 14:09:37.717: E/AndroidRuntime(360): Caused by: java.lang.ClassCastException:  
  com.example.abc.MainActivity
  03-18 14:09:37.717: E/AndroidRuntime(360):    at com.example.abc.MainActivity.onCreate 
  (MainActivity.java:30)
  03-18 14:09:37.717: E/AndroidRuntime(360):    at   
  android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
   03-18 14:09:37.717: E/AndroidRuntime(360):   at  
   android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
   03-18 14:09:37.717: E/AndroidRuntime(360):   ... 11 more

经过一些修改后正如第一个答案所说，我的代码没有崩溃，但我只能看到 android_mainfest 仍然相同的空白活动

package com.example.cricscore;

import android.app.Activity; 
import android.os.Bundle; 
import android.util.Log;
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.TextView; 

public class MainActivity extends Activity implements OnClickListener { 

// Private member field to keep track of the count 
private int mCount = 0; 
/** Called when the activity is first created. 
 * @param OnClickListener */
public void onCreate(Bundle savedInstanceState, android.view.View.OnClickListener 
OnClickListener){
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 


    Button buttonA = (Button) findViewById(R.id.button1);    
    buttonA.setOnClickListener((OnClickListener) );
    Button buttonB = (Button) findViewById(R.id.button2); 
    buttonB.setOnClickListener((OnClickListener) );
 }

   public void OnClickListener(View v) {

        switch (v.getId()) {
           case R.id.button1: 
               mCount++; 
               final TextView countTextView = (TextView) findViewById(R.id.textView1);
               countTextView.setText(""+ mCount); 
            break;
           case R.id.button2:
               mCount= mCount+2 ; 
               final TextView countTextView1 = (TextView) findViewById(R.id.textView1);
               countTextView1.setText(""+ mCount);
            break;


        }


   }

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}
 }

score 1 · Accepted Answer

setOnClickListener方法需要一个 View.OnClickListener 类型的参数。在这段代码中，您正在做的是获取Activity本身，并试图将其强制为它不是的：OnClickListener

Button buttonA = (Button) findViewById(R.id.button1);    
buttonA.setOnClickListener((OnClickListener) this); // <-- here
Button buttonB = (Button) findViewById(R.id.button2); 
buttonB.setOnClickListener((OnClickListener) this); // <-- and here too

您应该使用以下方法将您的活动声明为 OnClickListener：

public class MainActivity extends Activity implements OnClickListener

并且由于您已经有了onClick(View v)方法，因此应该解决问题。

java - 我使用多个 OnClickListeners 得到致命异常

1 回答 1

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