Question

今天我收到了NullPointerException报告。我无法在自己的手机上重现这个NullPointerException。

我真的找不到导致NullPointerException的原因。

以下是报告：

java.lang.NullPointerException
at com.dsf.sdf.ManActivity$25.onTouch(ManActivity.java:445)
at android.view.View.dispatchTouchEvent(View.java:3762)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
at com.android.internal.policy.impl.PhoneWindow$DecorView.
    (PhoneWindow.java:1674)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1109)
at android.app.Activity.dispatchTouchEvent(Activity.java:2086)
at com.android.internal.policy.impl.PhoneWindow$DecorView.
    dispatchTouchEvent(PhoneWindow.java:1658)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1785)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.
    run(ZygoteInit.java:876)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:634)
at dalvik.system.NativeStart.main(Native Method)

以下是第936行的代码：

sdff.setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            sdff.setBackgroundDrawable(getResources().
                getDrawable(R.drawable.pressed));
        } 

        else if (event.getAction() == MotionEvent.ACTION_UP) {
            if (play != null) {
                play.reset();
                play.release();
            }

            play = MediaPlayer.create(ManActivity.this,
                R.raw.sdff);
            play.start();
            sdff.setBackgroundDrawable(getResources().
                getDrawable(R.drawable.button));
        } 

        else if (event.getAction() == MotionEvent.ACTION_CANCEL) {
            sdff.setBackgroundDrawable(getResources().
                getDrawable(R.drawable.button));
        }

        return false;
    }
});

这是一个按下按钮时播放声音的简单按钮。

那导致异常的是什么？

编辑：

Code at line 445:

play = MediaPlayer.create(ManActivity.this,
    R.raw.bf);
play.start();
auth.setBackgroundDrawable(getResources().getDrawable(
    R.drawable.button));

Answer 1

Rajesh是对的，是什么代码@ ManActivity.java:455（第445行）。如果这是代码，它也可以使用以下作为你的touchlistener。

    sdff.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (event.getAction() == MotionEvent.ACTION_DOWN) {
                // dont use sdff, use v param that is passed in.
                v.setBackgroundDrawable(getResources()
                        .getDrawable(R.drawable.pressed));
            } else if (event.getAction() == MotionEvent.ACTION_UP) {
                if (play != null) {
                    play.reset();
                    play.release();
                }
                play = MediaPlayer.create(ManActivity.this,
                        R.raw.sdff);

                play.start();
                v.setBackgroundDrawable(getResources()
                        .getDrawable(R.drawable.button));
            } else if (event.getAction() == MotionEvent.ACTION_CANCEL) {
                v.setBackgroundDrawable(getResources()
                        .getDrawable(R.drawable.button));
            }
            return false;
        }
    });

无论如何，您是否尝试过调试应用程序？（右键单击包浏览器中的Project＆gt; Debug As＆gt; Android Application）。然后这将切换到调试透视图。找到断点窗格（窗口＆gt;显示视图＆gt;断点）。单击Add JAva execption Breakpoint按钮（带有“！”的“J”）。键入“Null”并双击出现的NullPointerException。

来自Play商店的NullPointerException报告

1 个答案: