Question

尝试创建自定义对话框。我创建了一个新的xml布局文件名dialog_result：然后在我的GuessActivity上，我有这个代码：

public class GuessActivity extends ActionBarActivity {

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

}

public void checkAnswer(View view){
    EditText userinput = (EditText) findViewById(R.id.inputLetter);
    String temp = userinput.getText().toString();
    char userletter = temp.charAt(0);

    Bundle fromplay = getIntent().getExtras();
    String temp2 = fromplay.getString("missing");
    char missingletter = temp2.charAt(0);

    Log.d ("temp2", temp2);

    if(userletter == missingletter){
        Log.d ("right", "right");
        resultDialogBox();
    } else {
        Log.d ("wrong", "wrong");
        resultDialogBox();
    }


}

public void resultDialogBox(){
    Dialog resultbox = new Dialog(GuessActivity.this);
    TextView result = (TextView) findViewById(R.id.resulttext);
    resultbox.setContentView(R.layout.dialog_result);

    result.setText("Correct");

    resultbox.show();
}

}

对于我的生活，我不知道应用程序崩溃的原因。它一直工作到log.d（“右”，“右”）和/或log.d（“错误”，“错误”），然后它在调用resultDialogBox时崩溃。

logcat：

04-28 10:43:33.705: D/temp2(7079): n
04-28 10:43:33.705: D/right(7079): right
04-28 10:43:33.715: D/AndroidRuntime(7079): Shutting down VM
04-28 10:43:33.715: W/dalvikvm(7079): threadid=1: thread exiting with uncaught exception (group=0x4161c8b0)
04-28 10:43:33.725: E/AndroidRuntime(7079): FATAL EXCEPTION: main
04-28 10:43:33.725: E/AndroidRuntime(7079): java.lang.IllegalStateException: Could not execute method of the activity
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.view.View$1.onClick(View.java:3814)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.view.View.performClick(View.java:4421)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.view.View$PerformClick.run(View.java:17903)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.os.Handler.handleCallback(Handler.java:730)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.os.Handler.dispatchMessage(Handler.java:92)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.os.Looper.loop(Looper.java:213)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.app.ActivityThread.main(ActivityThread.java:5225)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at java.lang.reflect.Method.invokeNative(Native Method)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at java.lang.reflect.Method.invoke(Method.java:525)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at dalvik.system.NativeStart.main(Native Method)
04-28 10:43:33.725: E/AndroidRuntime(7079): Caused by: java.lang.reflect.InvocationTargetException
04-28 10:43:33.725: E/AndroidRuntime(7079):     at java.lang.reflect.Method.invokeNative(Native Method)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at java.lang.reflect.Method.invoke(Method.java:525)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at android.view.View$1.onClick(View.java:3809)
04-28 10:43:33.725: E/AndroidRuntime(7079):     ... 11 more
04-28 10:43:33.725: E/AndroidRuntime(7079): Caused by: java.lang.NullPointerException
04-28 10:43:33.725: E/AndroidRuntime(7079):     at com.johnyeung.letterhunter.GuessActivity.resultDialogBox(GuessActivity.java:54)
04-28 10:43:33.725: E/AndroidRuntime(7079):     at com.johnyeung.letterhunter.GuessActivity.checkAnswer(GuessActivity.java:40)
04-28 10:43:33.725: E/AndroidRuntime(7079):     ... 14 more
04-28 10:43:37.899: D/libEGL(7200): loaded /vendor/lib/egl/libEGL_adreno.so
04-28 10:43:37.899: D/libEGL(7200): loaded /vendor/lib/egl/libGLESv1_CM_adreno.so
04-28 10:43:37.899: D/libEGL(7200): loaded /vendor/lib/egl/libGLESv2_adreno.so
04-28 10:43:37.899: I/Adreno-EGL(7200): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build:  (CL4169980)
04-28 10:43:37.899: I/Adreno-EGL(7200): OpenGL ES Shader Compiler Version: 17.01.10.SPL
04-28 10:43:37.899: I/Adreno-EGL(7200): Build Date: 12/01/13 Sun
04-28 10:43:37.899: I/Adreno-EGL(7200): Local Branch: 
04-28 10:43:37.899: I/Adreno-EGL(7200): Remote Branch: 
04-28 10:43:37.899: I/Adreno-EGL(7200): Local Patches: 
04-28 10:43:37.899: I/Adreno-EGL(7200): Reconstruct Branch: 
04-28 10:43:37.940: D/OpenGLRenderer(7200): Enabling debug mode 0

Answer 1

错误日志表明你在第54行有NullPointerException。你有检查吗？

我认为有问题的代码是

result.setText("Correct");

它为null，因为您通过

实例化result

TextView result = (TextView) findViewById(R.id.resulttext);

findViewById是在活动上调用的方法，而不是在Dialog上。如果您的活动没有Null，则返回TextView。

根据documentation of Dialogs，您不应直接使用Dialog。请改用AlertDialog.Builder：

// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

// 2. Chain together various setter methods to set the dialog characteristics
builder.setMessage(R.string.dialog_message)
       .setTitle(R.string.dialog_title);

// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();

Answer 2

您没有在对话框中设置内容视图。试试这个。

public void resultDialogBox(){

Dialog resultbox = new Dialog(GuessActivity.this);
resultbox.setContentView(R.layout.dialog_result);
TextView result = (TextView)resultbox.findViewById(R.id.resulttext);
result.setText("Correct");

resultbox.show();

}

Android dev自定义对话框不会出现

2 个答案: