Question

我有活动＆＃39; A＆＃39;活动＆＃39; B＆＃39;活动＆＃39; C＆＃39;活动＆＃39; D＆＃39;活动＆＃39; E＆＃39;，活动＆＃39; E＆＃39; 。我想退出Activity点击onBackPressed（）。当我运行应用程序时，它会转到活动＆＃39; A＆＃39;它不会退出应用程序。我该如何实现呢？

这是我的代码

public class MainActivity extends Activity {

    TableLayout table_layout;
    EditText firstname_et, lastname_et;
    Button addmem_btn;

    DatabaseHelper databaseHelper = new DatabaseHelper(this);
    protected SQLiteDatabase db;

    ProgressDialog PD;
    ImageView imgButtonBack;

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

        table_layout = (TableLayout) findViewById(R.id.tableLayout_PerformanceReport);


         //ImageView imgButtonBack;
         imgButtonBack = (ImageView)findViewById(R.id.imagBackButton);
         imgButtonBack.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent(MainActivity.this, Employee_List.class);
                i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
                //finish();
            }
        });


    }

}
    @Override
    public void onBackPressed()
    {
        AlertDialog.Builder alertbox = new AlertDialog.Builder(MainActivity.this);

        alertbox.setTitle("Do you wish to exit ?");
        alertbox.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) { 
               // finish used for destroyed activity
                finish();
            }
        });

        alertbox.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
                    // Nothing will be happened when clicked on no button 
                    // of Dialog     
          }
        });

        alertbox.show();
   }
}

感谢Appreciate。

Answer 1

您可以在onBackPressed：

中尝试此操作

@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    Intent intent = new Intent(Intent.ACTION_MAIN);
    intent.addCategory(Intent.CATEGORY_HOME);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);
}

退出应用程序。对我来说工作正常。希望它有所帮助。

Answer 2

在您打开新活动时调用this.finish()（从活动A到其他活动）。在你的情况下写这个

public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent i = new Intent(MainActivity.this, Employee_List.class);
                i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
                MainActivity.this.finish();
            }
        });

Answer 3

你可以这样做 -

private exit = false;
public void onBackPressed() {
    if (exit)
        Home.this.finish();
    else {
        Toast.makeText(this, "Press Back again to Exit.",
                Toast.LENGTH_SHORT).show();
        exit = true;
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                exit = false;
            }
        }, 3 * 1000);

    }

}

如何在Android中使用onBackPressed（）？

3 个答案: