Java 安卓&x201C；不幸的是，<；应用程序>；已停止；

我认为应用程序停止了

setContentView（R.layout.main）

或

TextState=（EditText）findViewById（R.id.TextState）和更多，但我不知道需要做什么。对不起错误的帖子，但请帮助我

\res\layout land\main.xml:
-需要一个水平接口



主要活动：

public class MainActivity extends Activity implements OnClickListener {
EditText TextState;
Button Up;
Button Down;
Button Left;
Button Right;
@Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

    TextState = (EditText) findViewById(R.id.TextState);

    Up = (Button) findViewById(R.id.Up);
    Down = (Button) findViewById(R.id.Down);
    Left = (Button) findViewById(R.id.Left);
    Right = (Button) findViewById(R.id.Right);

    Up.setOnClickListener(this);
    Down.setOnClickListener(this);
    Right.setOnClickListener(this);
    Left.setOnClickListener(this);
}
    @Override
    public void onClick(View v) {
         switch (v.getId()) {
            case R.id.Up:

              // TODO:
                TextState.setText("Едем вперед");

              break;
            case R.id.Down:

                  // TODO:
                TextState.setText("Едем назад");

              break;
            case R.id.Right:

                  // TODO:
                TextState.setText("Едем направо");

              break;
            case R.id.Left:

                  // TODO:
                TextState.setText("Едем налево");

              break;
            default:
              break;
    }

    }}

catlog：

12-18 20:25:44.299: D/AndroidRuntime(647): Shutting down VM
12-18 20:25:44.299: W/dalvikvm(647): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
12-18 20:25:44.319: E/AndroidRuntime(647): FATAL EXCEPTION: main
12-18 20:25:44.319: E/AndroidRuntime(647): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.app/com.example.app.MainActivity}: java.lang.NullPointerException
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.os.Handler.dispatchMessage(Handler.java:99)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.os.Looper.loop(Looper.java:137)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.ActivityThread.main(ActivityThread.java:4745)
12-18 20:25:44.319: E/AndroidRuntime(647):  at java.lang.reflect.Method.invokeNative(Native Method)
12-18 20:25:44.319: E/AndroidRuntime(647):  at java.lang.reflect.Method.invoke(Method.java:511)
12-18 20:25:44.319: E/AndroidRuntime(647):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-18 20:25:44.319: E/AndroidRuntime(647):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-18 20:25:44.319: E/AndroidRuntime(647):  at dalvik.system.NativeStart.main(Native Method)
12-18 20:25:44.319: E/AndroidRuntime(647): Caused by: java.lang.NullPointerException
12-18 20:25:44.319: E/AndroidRuntime(647):  at com.example.app.MainActivity.onCreate(MainActivity.java:32)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.Activity.performCreate(Activity.java:5008)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
12-18 20:25:44.319: E/AndroidRuntime(647):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
12-18 20:25:44.319: E/AndroidRuntime(647):  ... 11 more
12-18 20:26:10.839: I/Process(647): Sending signal. PID: 647 SIG: 9
12-18 20:26:16.799: E/Trace(662): error opening trace file: No such file or directory (2)
12-18 20:26:17.249: D/AndroidRuntime(662): Shutting down VM
12-18 20:26:17.249: W/dalvikvm(662): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
12-18 20:26:17.260: E/AndroidRuntime(662): FATAL EXCEPTION: main
12-18 20:26:17.260: E/AndroidRuntime(662): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.app/com.example.app.MainActivity}: java.lang.NullPointerException
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.os.Handler.dispatchMessage(Handler.java:99)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.os.Looper.loop(Looper.java:137)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.ActivityThread.main(ActivityThread.java:4745)
12-18 20:26:17.260: E/AndroidRuntime(662):  at java.lang.reflect.Method.invokeNative(Native Method)
12-18 20:26:17.260: E/AndroidRuntime(662):  at java.lang.reflect.Method.invoke(Method.java:511)
12-18 20:26:17.260: E/AndroidRuntime(662):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-18 20:26:17.260: E/AndroidRuntime(662):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-18 20:26:17.260: E/AndroidRuntime(662):  at dalvik.system.NativeStart.main(Native Method)
12-18 20:26:17.260: E/AndroidRuntime(662): Caused by: java.lang.NullPointerException
12-18 20:26:17.260: E/AndroidRuntime(662):  at com.example.app.MainActivity.onCreate(MainActivity.java:32)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.Activity.performCreate(Activity.java:5008)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
12-18 20:26:17.260: E/AndroidRuntime(662):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
12-18 20:26:17.260: E/AndroidRuntime(662):  ... 11 more
12-18 20:26:49.719: I/Process(662): Sending signal. PID: 662 SIG: 9

我在这里发现了你的错误



EditText文本状态

TextState=（EditText）findViewById（R.id.TextState）


改为
TextView TextState

TextState=（TextView）findViewById（R.id.TextState）


或者在XML文件中

<EditText
android:id="@+id/TextState"/>



只要看一下你的日志，你就会在第32行得到一个NPE。可能findViewById没有找到您的视图，并且该字段为空。
您应该在第32行中找到问题

com.example.app.MainActivity.onCreate（MainActivity.java:32）
更改编辑文本的文本视图。问题已解决
TextState
是一个
TextView
，而不是一个
EditText
，正如邹祖所说，TextState是一个TextView而不是一个EditText替换TextState=（EditText）findViewById（R.id.TextState）；使用TextState=（TextView）findViewById（R.id.TextState）；我这样做了，但没有帮助您在布局文件夹中有main.xml文件吗？如果没有，那就是个问题。手机可能正在尝试从布局文件夹中删除。另外，请提及第32I行中的内容我在布局文件夹中有main.xml。将TextState=（EditText）findViewById（R.id.TextState）更改为TextState=（TextView）findViewById（R.id.TextState）没有帮助（（如我所说更改为xml^^^请尝试
Caused by: java.lang.NullPointerException
at com.example.app.MainActivity.onCreate(MainActivity.java:32)