Android - 单击按钮时播放声音 - 强制关闭

Question

我正在尝试编写一个应用程序，该应用程序将在单击图像时播放声音剪辑。剪辑大约 1 秒长。每当打开应用程序时，它都会强制关闭。这是我的编码。为什么会强制关闭？

主要活动

package com.jeremy.vroom;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.media.MediaPlayer;
import android.widget.Button;
import android.view.View.OnClickListener;
import android.view.View;

public class MainActivity extends Activity {

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

        Button zero = (Button)this.findViewById(R.id.btnZero);
        zero.setOnClickListener(new OnClickListener() {

            public void onClick(View view) {     
                new Thread(){
                    public void run(){
                        MediaPlayer mp = MediaPlayer.create(MainActivity.this, R.raw.rev);   
                        mp.start();
                    }
                }.start();
            }
        });
    }

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

activitymain.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" >



<ImageView
    android:id="@+id/btnZero"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/uro5" 
    android:clickable="true"
    android:contentDescription="@string/desc" ></ImageView>

日志

08-03 17:21:29.156: D/AndroidRuntime(272): Shutting down VM
08-03 17:21:29.156: W/dalvikvm(272): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
08-03 17:21:29.298: E/AndroidRuntime(272): FATAL EXCEPTION: main
08-03 17:21:29.298: E/AndroidRuntime(272): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jeremy.vroom/com.jeremy.vroom.MainActivity}: java.lang.ClassCastException: android.widget.ImageView
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.os.Looper.loop(Looper.java:123)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.ActivityThread.main(ActivityThread.java:4627)
08-03 17:21:29.298: E/AndroidRuntime(272):  at java.lang.reflect.Method.invokeNative(Native Method)
08-03 17:21:29.298: E/AndroidRuntime(272):  at java.lang.reflect.Method.invoke(Method.java:521)
08-03 17:21:29.298: E/AndroidRuntime(272):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-03 17:21:29.298: E/AndroidRuntime(272):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-03 17:21:29.298: E/AndroidRuntime(272):  at dalvik.system.NativeStart.main(Native Method)
08-03 17:21:29.298: E/AndroidRuntime(272): Caused by: java.lang.ClassCastException: android.widget.ImageView
08-03 17:21:29.298: E/AndroidRuntime(272):  at com.jeremy.vroom.MainActivity.onCreate(MainActivity.java:18)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-03 17:21:29.298: E/AndroidRuntime(272):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
08-03 17:21:29.298: E/AndroidRuntime(272):  ... 11 more
08-03 17:21:32.588: I/Process(272): Sending signal. PID: 272 SIG: 9

提前感谢您的帮助

Answer 1

使用

ImageView zero = (ImageView)findViewById(R.id.btnZero);

而不是

 Button zero = (Button)this.findViewById(R.id.btnZero);

Answer 2

尝试改变：

Button zero = (Button)this.findViewById(R.id.btnZero);

到

Button zero = (Button) findViewById(R.id.btnZero);

看看有没有帮助。

Answer 3

在您的 XML 中，您已将 btnZero 声明为 ImageView，而在代码中您将其引用为 Button。这会导致您的 ClassCastException。尝试使用：

ImageView zero = (ImageView)findViewById(R.id.btnZero);

而不是

 Button zero = (Button)this.findViewById(R.id.btnZero);