Android 单击按钮设置铃声（错误）

“不幸的是，zilsesiayaryapma已停止”涉及错误 “设为铃声”（buton1）您不能设置铃声 让别人告诉我怎么做

MainActivity.java

public class MainActivity extends Activity implements OnClickListener  {

Button buton1;
MediaPlayer mp;
Context context;

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

    context = this ;
    String name = "american_crow.mp3";

    File file = new File(Environment.getExternalStorageDirectory(),
            "/myRingtonFolder/Audio/");
    if (!file.exists()) {
        file.mkdirs();
    }

    String path = Environment.getExternalStorageDirectory()
            .getAbsolutePath() + "/myRingtonFolder/Audio/";

    File f = new File(path + "/", name + ".mp3");

    Uri mUri = Uri.parse("android.resource://"
            + context.getPackageName() + "/raw/" + name);
    ContentResolver mCr = context.getContentResolver();
    AssetFileDescriptor soundFile;
    try {
        soundFile = mCr.openAssetFileDescriptor(mUri, "r");
    } catch (FileNotFoundException e) {
        soundFile = null;
    }
    try {
        byte[] readData = new byte[1024];
        FileInputStream fis = soundFile.createInputStream();
        FileOutputStream fos = new FileOutputStream(f);
        int i = fis.read(readData);

        while (i != -1) {
            fos.write(readData, 0, i);
            i = fis.read(readData);
        }

        fos.close();
    } catch (IOException io) {
    }
    ContentValues values = new ContentValues();
    values.put(MediaStore.MediaColumns.DATA, f.getAbsolutePath());
    values.put(MediaStore.MediaColumns.TITLE, name);
    values.put(MediaStore.MediaColumns.MIME_TYPE, "audio/mp3");
    values.put(MediaStore.MediaColumns.SIZE, f.length());
    values.put(MediaStore.Audio.Media.ARTIST, R.string.app_name);
    values.put(MediaStore.Audio.Media.IS_RINGTONE, true);
    values.put(MediaStore.Audio.Media.IS_NOTIFICATION, true);
    values.put(MediaStore.Audio.Media.IS_ALARM, true);
    values.put(MediaStore.Audio.Media.IS_MUSIC, true);

    Uri uri = MediaStore.Audio.Media.getContentUriForPath(f
            .getAbsolutePath());
    Uri newUri = mCr.insert(uri, values);

    try {
        RingtoneManager.setActualDefaultRingtoneUri(context,
                RingtoneManager.TYPE_RINGTONE, newUri);
        Settings.System.putString(mCr, Settings.System.RINGTONE,
                newUri.toString());
    } catch (Throwable t) {

        Toast.makeText(MainActivity.this, "American Crow",
                Toast.LENGTH_SHORT).show();
    }


    buton1 = (Button) findViewById(R.id.button1);
    buton1.setOnClickListener(this);
}




@Override
public void onClick(View v) {
    mp = MediaPlayer.create(MainActivity.this,
            R.raw.american_crow);
    mp.start();
    Toast.makeText(MainActivity.this, "American Crow",
            Toast.LENGTH_SHORT).show();
}


}

日志信息如下

    05-27 20:26:14.866: W/ApplicationPackageManager(16084): getCSCPackageItemText()
05-27 20:26:14.911: D/AndroidRuntime(16084): Shutting down VM
05-27 20:26:14.911: W/dalvikvm(16084): threadid=1: thread exiting with uncaught exception (group=0x41876c08)
05-27 20:26:14.916: E/AndroidRuntime(16084): FATAL EXCEPTION: main
05-27 20:26:14.916: E/AndroidRuntime(16084): Process: com.example.zilsesiayaryapma, PID: 16084
05-27 20:26:14.916: E/AndroidRuntime(16084): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.zilsesiayaryapma/com.example.zilsesiayaryapma.MainActivity}: java.lang.NullPointerException
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.ActivityThread.access$900(ActivityThread.java:161)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.os.Handler.dispatchMessage(Handler.java:102)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.os.Looper.loop(Looper.java:157)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.ActivityThread.main(ActivityThread.java:5356)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at java.lang.reflect.Method.invokeNative(Native Method)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at java.lang.reflect.Method.invoke(Method.java:515)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at dalvik.system.NativeStart.main(Native Method)
05-27 20:26:14.916: E/AndroidRuntime(16084): Caused by: java.lang.NullPointerException
05-27 20:26:14.916: E/AndroidRuntime(16084):    at com.example.zilsesiayaryapma.MainActivity.onCreate(MainActivity.java:62)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.Activity.performCreate(Activity.java:5426)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
05-27 20:26:14.916: E/AndroidRuntime(16084):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269)
05-27 20:26:14.916: E/AndroidRuntime(16084):    ... 11 more

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帮帮我…

您从不初始化上下文

Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    context =this;

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不幸的是zilsesiayaryapma已经停止了我也这么做了。我认为这是错误的elsewhere@useromer10不，这不能是因为，如果你像上面那样初始化它应该是好的。错误指向哪里？应用程序已停止。05-27 20:17:15.976:E/AndroidRuntime（14488）：java.lang.RuntimeException:无法启动活动组件信息{com.example.zilsesiayaryapma/com.example.zilsesiayaryapma.MainActivity}:java.lang。NullPointerException@useromer10用新的stacktrace更新您的帖子。这是不同的problem@useromer10还可以通过查看stacktraceNew问题来指示发生异常的行@第62行指示第62行