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我正在开发这个秒表应用程序，并且在运行我的应用程序时，我一直在关闭这种奇怪的力量。

在模拟器上运行应用程序时，应用程序启动得很好，我可以看到布局和所有内容，通常可以启动秒表，停止并重置它，但是当我尝试再次启动它时，它通常会崩溃，而其他有时，我可以在崩溃之前多次启动、重置和启动秒表，而其他一些时候我会在第一次启动时崩溃

我是android开发的新手，所以任何帮助都将不胜感激。感谢您

这是我的 Java 文件：

package com.tutorial.stopwatch;

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.view.Menu;
import android.app.Activity;  
import android.content.res.Configuration;
import android.widget.LinearLayout;
import android.widget.TextView;  
import android.graphics.Typeface;  
import android.os.Bundle;  
import android.util.DisplayMetrics;  
import android.util.TypedValue;
import android.view.View;  
import android.widget.Button;  

public class MainActivity extends Activity {

    private TextView tempTextView; //Temporary TextView
    private Button tempBtn; //Temporary Button 
    private Handler mHandler = new Handler();
    private long startTime;
    private long elapsedTime;
    private final int REFRESH_RATE = 100;
    private String hours,minutes,seconds,milliseconds;
    private long secs,mins,hrs,msecs;
    private boolean stopped = false;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        checkScreenDensity();

        /*-------Setting the TextView Fonts-----------*/  

        Typeface fonttimer = Typeface.createFromAsset(getAssets(), "roboto.ttf");
        tempTextView = (TextView) findViewById(R.id.timer);  
        tempTextView.setTypeface(fonttimer);
        tempTextView = (TextView) findViewById(R.id.timerMs);  
        tempTextView.setTypeface(fonttimer);
        tempTextView = (TextView) findViewById(R.id.timerHs);  
        tempTextView.setTypeface(fonttimer);

        Typeface font = Typeface.createFromAsset(getAssets(), "roboto.ttf");
        tempTextView = (TextView) findViewById(R.id.backgroundText);  
        tempTextView.setTypeface(font);  
        Button tempBtn = (Button)findViewById(R.id.startButton);  
        tempBtn.setTypeface(font);  
        tempBtn = (Button)findViewById(R.id.resetButton);  
        tempBtn.setTypeface(font);  
        tempBtn = (Button)findViewById(R.id.stopButton);  
        tempBtn.setTypeface(font);  

    }


    private void checkScreenDensity(){  
        tempTextView = (TextView)findViewById(R.id.backgroundText);  
        switch (getResources().getDisplayMetrics().densityDpi) {  
        case DisplayMetrics.DENSITY_LOW:  
            tempTextView.setVisibility(View.GONE);  
            break;  
        case DisplayMetrics.DENSITY_MEDIUM:  
            tempTextView.setVisibility(View.GONE);  
            break;  
        case DisplayMetrics.DENSITY_HIGH:  
            tempTextView.setVisibility(View.VISIBLE);  
            break;  
        }  
    }  

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }



    //---------- on click procedures - id from layout.xml -----------

    public void startClick (View view){
        showStopButton();
        if(stopped){
            startTime = System.currentTimeMillis() - elapsedTime;
        }
        else{
            startTime = System.currentTimeMillis();
        }
        mHandler.removeCallbacks(startTimer);
        mHandler.postDelayed(startTimer, 0);
    }

    public void stopClick (View view){
        hideStopButton();
        mHandler.removeCallbacks(startTimer);
        stopped = true;
    }

    public void resetClick (View view){
        stopped = false;
        ((TextView)findViewById(R.id.timer)).setText("00:00");
        ((TextView)findViewById(R.id.timerMs)).setText(":00");
        ((TextView)findViewById(R.id.timerHs)).setText("00:");
    }

    //---------- Button change (start/reset to stop button)
    private void showStopButton(){
        ((Button)findViewById(R.id.startButton)).setVisibility(View.GONE);
        ((Button)findViewById(R.id.resetButton)).setVisibility(View.GONE);
        ((Button)findViewById(R.id.stopButton)).setVisibility(View.VISIBLE);
    }

    private void hideStopButton(){
        ((Button)findViewById(R.id.startButton)).setVisibility(View.VISIBLE);
        ((Button)findViewById(R.id.resetButton)).setVisibility(View.VISIBLE);
        ((Button)findViewById(R.id.stopButton)).setVisibility(View.GONE);
    }

    //-------- time from MiliSeconds to regular time ---------------------------------

    private void updateTimer (float time){
        secs = (long)(time/1000);
        mins = (long)((time/1000)/60);
        hrs = (long)(((time/1000)/60)/60);

        /* Setting the timer text to the elapsed time */
        ((TextView)findViewById(R.id.timerHs)).setText(hours + ":");
        ((TextView)findViewById(R.id.timer)).setText(minutes + ":" + seconds);
        ((TextView)findViewById(R.id.timerMs)).setText(":" + milliseconds);

        /* Convert the seconds to String
         * and format to ensure it has
         * a leading zero when required
         */
        secs = secs % 60;
        seconds=String.valueOf(secs);
        if(secs == 0){
            seconds = "00";
        }
        if(secs <10 && secs > 0){
            seconds = "0"+seconds;
        }

        /* Convert the minutes to String and format the String */

        mins = mins % 60;
        minutes=String.valueOf(mins);
        if(mins == 0){
            minutes = "00";
        }
        if(mins <10 && mins > 0){
            minutes = "0"+minutes;
        }

        /* Convert the hours to String and format the String */

        hours=String.valueOf(hrs);
        if(hrs == 0){
            hours = "00";
        }
        if(hrs <10 && hrs > 0){
            hours = "0"+hours;
        }

        /* milliseconds  */

        milliseconds = String.valueOf((long)time);
        if(milliseconds.length()==3){
            milliseconds = "0"+milliseconds;
        }
        if(milliseconds.length()<=1){
            milliseconds = "00";
        }
        milliseconds = milliseconds.substring(milliseconds.length()-3,   milliseconds.length()-1);




    }

    //------------- Timer Runnnable ---------------------------------------------------

    private Runnable startTimer = new Runnable() {
           public void run() {
               elapsedTime = System.currentTimeMillis() - startTime;
               updateTimer(elapsedTime);
               mHandler.postDelayed(this,REFRESH_RATE);
            }
        };

    //------------------ screen orientation fix ---------------------------------------

        @Override
        public void onConfigurationChanged(Configuration newConfig) {
            super.onConfigurationChanged(newConfig);
            if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
                TextView timer = (TextView) findViewById(R.id.timer);
                timer.setTextSize(TypedValue.COMPLEX_UNIT_SP, 90);
                TextView timerMs = (TextView) findViewById(R.id.timerMs);
                timerMs.setTextSize(TypedValue.COMPLEX_UNIT_SP, 40);

            }
            else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {
                TextView timer = (TextView) findViewById(R.id.timer);
                timer.setTextSize(TypedValue.COMPLEX_UNIT_SP, 70);
                TextView timerMs = (TextView) findViewById(R.id.timerMs);
                timerMs.setTextSize(TypedValue.COMPLEX_UNIT_SP, 30);

            }
        }



}

我的 XML 文件：

<?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">  
        <FrameLayout  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        android:id="@+id/parentFrameLayout">  
            <LinearLayout  
            android:orientation="vertical"  
            android:layout_width="fill_parent"  
            android:layout_height="fill_parent"  
            android:id="@+id/linearLayout">  
                <LinearLayout  
                android:orientation="horizontal"  
                android:gravity="center"  
                android:layout_width="fill_parent"  
                android:layout_height="wrap_content"  
>

                    <TextView
                     android:id="@+id/timerHs"
                     style="@style/timerText"
                     android:layout_width="wrap_content"
                     android:paddingTop="30sp"
                     android:text="@string/timerHs"
                     android:textSize="30sp"
                     android:paddingRight="5sp"
                     android:paddingBottom="60sp" />
                    <TextView  
                     style="@style/timerText"
                     android:text="@string/timer"  
                     android:id="@+id/timer"
                     android:layout_width="wrap_content" >  
                     </TextView>
                     <TextView
                     style="@style/timerText"
                     android:text="@string/timerMs"
                     android:id="@+id/timerMs"
                     android:textSize="30sp"
                     android:paddingTop="30sp"
                     android:layout_width="wrap_content"
                     android:paddingLeft="5sp"
                     android:paddingBottom="60sp">
                     </TextView>                     
                </LinearLayout>  
                <LinearLayout  
                android:orientation="horizontal"  
                android:layout_gravity="center_horizontal"  
                android:gravity="center"  
                android:layout_width="wrap_content"  
                android:layout_height="wrap_content"  
                android:layout_marginTop="20dp"  
                android:background="@drawable/buttonarea">  
                    <Button  
                    style="@style/buttonText"  
                    android:layout_marginLeft="5dp"  
                    android:layout_marginRight="5dp"  
                    android:background="@drawable/stopbuttonstates"  
                    android:textColor="#7A1100"  
                    android:shadowColor="#DF726E"  
                    android:text="@string/stopText"  
                    android:id="@+id/stopButton"  
                    android:visibility="gone"
                    android:onClick="stopClick">  
                    </Button>  
                    <Button  
                    style="@style/buttonText"  
                    android:layout_marginLeft="5dp"  
                    android:background="@drawable/startbuttonstates"  
                    android:textColor="#000000"  
                    android:shadowColor="#FBEBC5"  
                    android:text="@string/startText"  
                    android:id="@+id/startButton"
                    android:onClick="startClick">  
                    </Button>  
                    <Button  
                    style="@style/buttonText"  
                    android:layout_marginRight="5dp"  
                    android:background="@drawable/resetbuttonstates"  
                    android:textColor="#2E2E2E"  
                    android:shadowColor="#959597"  
                    android:text="@string/resetText"  
                    android:id="@+id/resetButton"
                    android:onClick="resetClick">  
                    </Button>  
                </LinearLayout>  
                <LinearLayout  
                android:orientation="horizontal"  
                android:layout_width="wrap_content"  
                android:layout_height="wrap_content"  
                android:layout_gravity="center_horizontal">  
                    <ImageView  
                    android:src="@drawable/hline"  
                    android:layout_height="wrap_content"  
                    android:layout_gravity="center"  
                    android:layout_marginTop="20dp"  
                    android:layout_marginBottom="10dp"  
                    android:layout_width="wrap_content">  
                    </ImageView>  
                </LinearLayout>  
                <ScrollView  
                android:layout_width="fill_parent"  
                android:layout_height="wrap_content"  
                android:layout_gravity="center_horizontal"  
                android:id="@+id/scrollView">  
                    <TextView  
                    style="@style/backgroundText"    
                    android:text="@string/backgroundText"  
                    android:id="@+id/backgroundText">  
                    </TextView>  
                </ScrollView>  
            </LinearLayout>  
        </FrameLayout>  
        <RelativeLayout  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignParentBottom="true" >  
            <LinearLayout  
            android:orientation="vertical"  
            android:layout_width="fill_parent"  
            android:layout_height="wrap_content"  
            android:background="#000000">  
                <TextView  
                android:layout_width="fill_parent"  
                android:layout_height="wrap_content"  
                android:gravity="center"  
                android:text="@string/adsText">  
                </TextView>  
            </LinearLayout>  
        </RelativeLayout>  
    </RelativeLayout>

字符串：

<?xml version="1.0" encoding="utf-8"?>  

<resources>  
    <string name="hello">Hello World, StopwatchActivity!</string>  
    <string name="app_name">Stopwatch</string>  
    <string name="timer">00:00</string>
    <string name="timerMs">:00</string>
    <string name="timerHs">00:</string>  
    <string name="startText">start</string>  
    <string name="resetText">reset</string>  
    <string name="stopText">stop</string>  
    <string name="backgroundText">Stopwatch</string>  
    <string name="adsText">Ads Go Here</string>
    <string name="menu_settings">Settings</string>
    <string name="title_activity_main">MainActivity</string>

和日志：（应用程序在此日志中的第一次启动时崩溃）

09-27 17:05:54.980: D/dalvikvm(920): GC_CONCURRENT freed 65K, 3% free 8410K/8583K, paused 107ms+8ms, total 211ms
09-27 17:05:54.980: D/dalvikvm(920): WAIT_FOR_CONCURRENT_GC blocked 65ms
09-27 17:05:55.271: D/dalvikvm(920): GC_FOR_ALLOC freed 2K, 3% free 8760K/8967K, paused 44ms, total 45ms
09-27 17:05:55.781: I/Choreographer(920): Skipped 57 frames!  The application may be doing too much work on its main thread.
09-27 17:05:55.822: D/gralloc_goldfish(920): Emulator without GPU emulation detected.
09-27 17:05:56.180: I/Choreographer(920): Skipped 34 frames!  The application may be doing too much work on its main thread.
09-27 17:06:10.250: D/AndroidRuntime(920): Shutting down VM
09-27 17:06:10.250: W/dalvikvm(920): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-27 17:06:10.280: E/AndroidRuntime(920): FATAL EXCEPTION: main
09-27 17:06:10.280: E/AndroidRuntime(920): java.lang.StringIndexOutOfBoundsException: length=2; regionStart=-1; regionLength=2
09-27 17:06:10.280: E/AndroidRuntime(920):  at java.lang.String.startEndAndLength(String.java:593)
09-27 17:06:10.280: E/AndroidRuntime(920):  at java.lang.String.substring(String.java:1474)
09-27 17:06:10.280: E/AndroidRuntime(920):  at com.tutorial.stopwatch.MainActivity.updateTimer(MainActivity.java:178)
09-27 17:06:10.280: E/AndroidRuntime(920):  at com.tutorial.stopwatch.MainActivity.access$3(MainActivity.java:125)
09-27 17:06:10.280: E/AndroidRuntime(920):  at com.tutorial.stopwatch.MainActivity$1.run(MainActivity.java:190)
09-27 17:06:10.280: E/AndroidRuntime(920):  at android.os.Handler.handleCallback(Handler.java:615)
09-27 17:06:10.280: E/AndroidRuntime(920):  at android.os.Handler.dispatchMessage(Handler.java:92)
09-27 17:06:10.280: E/AndroidRuntime(920):  at android.os.Looper.loop(Looper.java:137)
09-27 17:06:10.280: E/AndroidRuntime(920):  at android.app.ActivityThread.main(ActivityThread.java:4745)
09-27 17:06:10.280: E/AndroidRuntime(920):  at java.lang.reflect.Method.invokeNative(Native Method)
09-27 17:06:10.280: E/AndroidRuntime(920):  at java.lang.reflect.Method.invoke(Method.java:511)
09-27 17:06:10.280: E/AndroidRuntime(920):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-27 17:06:10.280: E/AndroidRuntime(920):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-27 17:06:10.280: E/AndroidRuntime(920):  at dalvik.system.NativeStart.main(Native Method)
4

2 回答 2

1

这是抛出的行StringIndexOutOfBoundsException：

milliseconds = milliseconds.substring(milliseconds.length()-3,   milliseconds.length()-1);

在此之前，如果长度小于 1，则将毫秒设置为“00”。请记住，如果毫秒的长度小于 3（如果它是“00”），那么在下一行你是将从-1开始获取一个子字符串，这将引发该异常。

也许你想要的是这样的：

milliseconds = milliseconds.substring(milliseconds.length()-2,   milliseconds.length());
于 2012-09-27T17:18:20.793 回答
1

你这里的线是错误的

milliseconds = milliseconds.substring(milliseconds.length()-3,   milliseconds.length()-1);

当毫秒设置为“00”时，您将子串从 -1 到 1。

你应该重新考虑你想要做什么，并抓住这个案例。

也许是这样：

    milliseconds = String.valueOf((long)time);
    if(milliseconds.length()==3){
        milliseconds = "0"+milliseconds;
    }
    if(milliseconds.length()<=1){
        milliseconds = "00";
    }
    else // Now wont substring when length <= 1 as there is no need.
    { 
        milliseconds = milliseconds.substring(milliseconds.length()-3,   milliseconds.length()-1);
    }
于 2012-09-27T17:18:21.337 回答