根据此链接中的教程，我刚刚创建了一个 android 对话框，该对话框将结果返回给主机活动（在我的项目中，它是 mainActivity）：http: //developer.android.com/guide/topics/ui/dialogs.html
它说为了处理你想在对话框中做的事件，你应该在对话框类中使用接口。然后，在宿主活动中，您应该实现此接口及其方法。但我注意到它只会在点击正面按钮时崩溃。这是我的代码：
public class dialogFragement extends DialogFragment {
public interface NoticeDialogListener {
public void onDialogPositiveClick(DialogFragment dialog);
public void onDialogNegativeClick(DialogFragment dialog);
}
NoticeDialogListener mListener;
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
try {
// Instantiate the NoticeDialogListener so we can send events to the host
mListener = (NoticeDialogListener) activity;
} catch (ClassCastException e) {
// The activity doesn't implement the interface, throw exception
throw new ClassCastException(activity.toString()
+ " must implement NoticeDialogListener");
}
}
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
builder.setView(inflater.inflate(R.layout.dialog_layout, null))
// Add action buttons
.setPositiveButton("Onayla", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
mListener.onDialogPositiveClick(dialogFragement.this);
}
})
.setNegativeButton("İptal et", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
mListener.onDialogNegativeClick(dialogFragement.this);
}
});
return builder.create();
}
}
在主要活动中：
public void onDialogPositiveClick(DialogFragment dialog) {
EditText et=(EditText)findViewById(R.id.editText1);
dosyaAdi=et.getText().toString();
dosyayaYaz();
}
LogCat 错误：
11-29 23:15:01.689: E/SensorManager(23506): thread start
11-29 23:15:16.684: E/AndroidRuntime(23506): FATAL EXCEPTION: main
11-29 23:15:16.684: E/AndroidRuntime(23506): java.lang.NullPointerException
11-29 23:15:16.684: E/AndroidRuntime(23506): at com.example.coordinates.MainActivity.onDialogPositiveClick(MainActivity.java:371)
11-29 23:15:16.684: E/AndroidRuntime(23506): at com.example.coordinates.dialogFragement$1.onClick(dialogFragement.java:54)
11-29 23:15:16.684: E/AndroidRuntime(23506): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:168)
11-29 23:15:16.684: E/AndroidRuntime(23506): at android.os.Handler.dispatchMessage(Handler.java:99)
11-29 23:15:16.684: E/AndroidRuntime(23506): at android.os.Looper.loop(Looper.java:137)
11-29 23:15:16.684: E/AndroidRuntime(23506): at android.app.ActivityThread.main(ActivityThread.java:4517)
11-29 23:15:16.684: E/AndroidRuntime(23506): at java.lang.reflect.Method.invokeNative(Native Method)
11-29 23:15:16.684: E/AndroidRuntime(23506): at java.lang.reflect.Method.invoke(Method.java:511)
11-29 23:15:16.684: E/AndroidRuntime(23506): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
11-29 23:15:16.684: E/AndroidRuntime(23506): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
11-29 23:15:16.684: E/AndroidRuntime(23506): at dalvik.system.NativeStart.main(Native Method)
dosyayaYaz() 函数：
private void dosyayaYaz(){
sm.unregisterListener(this); // this is the line 213
File myFile;
myFile= new File("sdcard/"+dosyaAdi.toString()+".csv");
try {
myFile.createNewFile();
FileOutputStream fOut = new FileOutputStream(myFile);
OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
myOutWriter.append("X Koor;Y Koor;Z Koor");
myOutWriter.append("\n");
dataReader=db.rawQuery("SELECT * FROM Koordinatlar", null);
while(dataReader.moveToNext()){
Float xDeg=(dataReader.getFloat(dataReader.getColumnIndex("xKoor")));
Float yDeg=(dataReader.getFloat(dataReader.getColumnIndex("yKoor")));
Float zDeg=(dataReader.getFloat(dataReader.getColumnIndex("zKoor")));
myOutWriter.append(String.format("%f", xDeg)+";"+String.format("%f", yDeg)+";"+String.format("%f", zDeg));
myOutWriter.append("\n");
}
Toast toast=Toast.makeText(getBaseContext(), "Başarıyla Dosyaya Yazıldı",Toast.LENGTH_SHORT);
toast.show();
sm.registerListener(this, myAccelerometer, SensorManager.SENSOR_DELAY_UI);
}
catch(IOException ex){
Toast toast=Toast.makeText(getBaseContext(), "Dosyaya yazma sırasında bir hata oluştu"+" "+ex.toString(),Toast.LENGTH_LONG);
toast.show();
}
}
创建函数：
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fm=getFragmentManager();
b1=(Button)findViewById(R.id.button1);
b2=(Button)findViewById(R.id.button2);
b3=(Button)findViewById(R.id.button3);
x=(TextView)findViewById(R.id.textView4);
y=(TextView)findViewById(R.id.textView5);
z=(TextView)findViewById(R.id.textView6);
sm=(SensorManager)getSystemService(Context.SENSOR_SERVICE);
myAccelerometer= sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sm.registerListener(this, myAccelerometer,SensorManager.SENSOR_DELAY_UI);
veritabani= new VeriTabani(this);
db=veritabani.getWritableDatabase();
valuesX= new ArrayList<Float>();
valuesY= new ArrayList<Float>();
valuesZ= new ArrayList<Float>();
zamanDiyagrami= new ArrayList<Float>();
b1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
grafikGoruntule();
}
});
b2.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
verileriSil();
}
});
b3.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
DialogFragment dialog = new dialogFragement();
dialog.show(fm, "MyDialogFragment");
}
});
}