android - 在捕获异常时在 Android 中显示自定义 AlertDialog

Question

我正在尝试在 catch block 中为用户显示警告消息。不同之处在于我的 try/catch 位于主 Activity 的 onCreate() 中，因此它会在应用程序打开后立即执行。

我试过这个(我有一个 OnClick() 用于在 Activity 的末尾使用 dialog.dismiss() 和 this.finish () 之后:

 catch (SQLException e) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this)
        .setTitle(getString(R.string.label_title_error))
        .setIcon(R.drawable.error_icon)
        .setMessage(getString(R.string.msg_error_sql))
        .setPositiveButton(getString(R.string.label_ok), this);

        AlertDialog dialogSQL = builder.create();
        dialogSQL.show();

        e.printStackTrace();
    }

我也试过这个:

   catch (NumberFormatException e) {
        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
        dialog.setTitle(getString(R.string.label_title_error));
        dialog.setIcon(R.drawable.error_icon);
        dialog.setMessage(getString(R.string.msg_error_numberformat));
        dialog.setNeutralButton(getString(R.string.label_ok), null);

        dialog.create().show();

        e.printStackTrace();
    }

在调试时强制异常，我可以看到它只是捕获异常，显示在 LogCat 中(作为警告)并保持流程直到它遇到另一个未处理的异常，然后显示默认的“抱歉!/强制关闭”安卓对话框。并且没有其他与 LogCat 中的对话框相关的异常。

为什么它不为捕获显示我的自定义 AlertDialogs？我考虑了 Builder 需要的上下文，但如果 onCreate() 中的 super() 在此代码之前，那么为什么它会显示消息？

谢谢大家

更新:好的，按照要求，这里有更多代码。

public class PinActivity extends Activity implements OnClickListener, android.content.DialogInterface.OnClickListener{

private Facade facade = null;

public static int INSERT_SAL = 0;
public static int INSERT_OK = 1;
public static int INSERT_CANCEL = 2;

EditText edtIniPin;
TextView txtSelecPin;
TextView txtCancPin;

int pinMaxLengthInt;

private String[] serviceNames;

@Override
protected void onCreate(Bundle savedInstanceState) {
    Log.v("FLUXO", "PIN -->> ON CREATE");
    super.onCreate(savedInstanceState);

    facade = Facade.getInstance();
    try {
        serviceNames = facade.loadApplication(this);
        facade.loadParameters(0);

        setContentView(R.layout.pin_screen);

        //Instanciando Views da Tela
        edtIniPin = (EditText) findViewById(R.id.editTextPin);
        txtSelecPin = (TextView) findViewById(R.id.btn_select_pin);
        txtCancPin = (TextView) findViewById(R.id.btn_cancel_pin);

        pinMaxLengthInt = Facade.getInstance().getPinSize();

        InputFilter[] FilterArray = new InputFilter[1];
        FilterArray[0] = new InputFilter.LengthFilter(pinMaxLengthInt);
        edtIniPin.setFilters(FilterArray);

        edtIniPin.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                if (edtIniPin.getText().length() > 0) {
                    txtCancPin.setText(getString(R.string.btn_clean));
                }
                else if (edtIniPin.getText().length() == 0){
                    txtCancPin.setText(getString(R.string.btn_exit));
                }
                else if (edtIniPin.getText().length() == Facade.getInstance().getPinSize()){
                    edtIniPin.setEnabled(false);
                }
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            }

            @Override
            public void afterTextChanged(Editable s) {
            }
        });

    } catch (SQLException e) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this)
        .setTitle(getString(R.string.label_title_error))
        .setIcon(R.drawable.error_icon)
        .setMessage(getString(R.string.msg_error_sql))
        .setPositiveButton(getString(R.string.label_ok), this);

        AlertDialog dialogSQL = builder.create();
        dialogSQL.show();

        e.printStackTrace();
    } catch (CorruptedAppException e) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this)
        .setTitle(getString(R.string.label_title_error))
        .setIcon(R.drawable.error_icon)
        .setMessage(getString(R.string.msg_error_corrupted))
        .setPositiveButton(getString(R.string.label_ok), this);

        AlertDialog dialogCorrupted = builder.create();
        dialogCorrupted.show();

        e.printStackTrace();
    } catch (NoServiceAvailableException e) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this)
        .setTitle(getString(R.string.label_title_error))
        .setIcon(R.drawable.error_icon)
        .setMessage(getString(R.string.msg_error_noservice))
        .setPositiveButton(getString(R.string.label_ok), this);

        AlertDialog dialogNoService = builder.create();
        dialogNoService.show();

        e.printStackTrace();
    } catch (NumberFormatException e) {

        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
        dialog.setTitle(getString(R.string.label_title_error));
        dialog.setIcon(R.drawable.error_icon);
        dialog.setMessage(getString(R.string.msg_error_numberformat));
        dialog.setNeutralButton(getString(R.string.label_ok), null);

        dialog.create().show();

    e.printStackTrace();
    }

}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Log.v("FLUXO", "PIN -->> ON ACTIVITY RESULT");
    if (resultCode == INSERT_OK) {
        String[] initCode = (String[]) data.getSerializableExtra("init_code");

        try {
            Facade.getInstance().insertInitCode(serviceNames[0], initCode, this);
        } catch (NumberFormatException e) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this)
            .setTitle(getString(R.string.label_title_error))
            .setIcon(R.drawable.error_icon)
            .setMessage(getString(R.string.msg_error_numberformat))
            .setPositiveButton(getString(R.string.label_ok), this);

            AlertDialog dialog = builder.create();
            dialog.show();

            e.printStackTrace();

        } catch (SQLException e) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this)
            .setTitle(getString(R.string.label_title_error))
            .setIcon(R.drawable.error_icon)
            .setMessage(getString(R.string.msg_error_sql))
            .setPositiveButton(getString(R.string.label_ok), this);

            AlertDialog dialog = builder.create();
            dialog.show();

            e.printStackTrace();

        } catch (CorruptedAppException e) {
            AlertDialog.Builder builder = new AlertDialog.Builder(this)
            .setTitle(getString(R.string.label_title_error))
            .setIcon(R.drawable.error_icon)
            .setMessage(getString(R.string.msg_error_corrupted))
            .setPositiveButton(getString(R.string.label_ok), this);

            AlertDialog dialog = builder.create();
            dialog.show();

            e.printStackTrace();
        }
    }
    else if (resultCode == INSERT_CANCEL){
        this.finish();
    }

}

@Override
protected void onStart() {
    Log.v("FLUXO", "PIN -->> ON START");
    super.onStart();
    txtSelecPin.setOnClickListener(this);
    txtCancPin.setOnClickListener(this);
}

@Override
protected void onResume() {
    Log.v("FLUXO", "PIN -->> ON RESUME");
    super.onResume();

    if (!facade.isInitialized(serviceNames[0], this)) {
        Intent itInicial = new Intent(this, InitialActivity.class);
        startActivityForResult(itInicial, INSERT_SAL);
    }
}

@Override
protected void onStop() {
    Log.v("FLUXO", "PIN -->> ON STOP");
    super.onStop();
}

@Override
protected void onPause() {
    Log.v("FLUXO", "PIN -->> ON PAUSE");
    super.onPause();
}

@Override
public void onBackPressed() {
    Log.v("FLUXO", "PIN -->> ON BACK KEY PRESSED");
    super.onBackPressed();
    moveTaskToBack(true);
}

@Override
protected void onDestroy() {
    Log.v("FLUXO", "PIN -->> ON DESTROY");
    super.onDestroy();
}

/**
 * Método chama próxima tela
 */
private void nextScreen(){
    Log.v("FLUXO", "PIN -->> NEXT SCREEN");
    Intent it = new Intent(this, ValueActivity.class);
    startActivity(it);
}

@Override
public void onClick(View v) {
       //lots of stuff (...)
}

@Override
public void onClick(DialogInterface dialog, int which) {
    dialog.dismiss();
    System.exit(0);
}

Answer 1

AlertDialog 通常需要其父上下文可见才能正常工作(根据我的经验；如果我错了，请有人纠正我)。除非有其他错误(如果没有完整的代码很难判断)，如果将它移到 onResume() 函数中，您可能会使其正常工作。