android.os.Process.killProcess(android.os.Process.myPid());中

Question

当我调用这个android.os.Process.killProcess（android.os.Process.myPid（））时，我遇到了一个错误;我的日志猫说它无法启动活动。正如我对使用 kill 进程的理解是杀死正在运行的任务，但当我使用它时，它表明它开始调用另一个活动。这是我的代码：

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(S_2nd_LoginActivity.this);
        alertDialogBuilder.setTitle("Are you sure you want to cancel?")
                          .setCancelable(false)
                          .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int id) {

                                android.os.Process.killProcess(android.os.Process.myPid());

                            }
                        })
                          .setNegativeButton("No", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                dialog.dismiss();
                            }
                          });
        AlertDialog alertDialog = alertDialogBuilder.create();
        alertDialog.show();

这是我的日志猫：

03-04 18:28:43.805: E/AndroidRuntime(19417): java.lang.RuntimeException: Unable to  start activity ComponentInfo{ph.com.example.Project/ph.com.example.Project.MainActivity}: java.lang.NullPointerException
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.ActivityThread.access$500(ActivityThread.java:122)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.os.Looper.loop(Looper.java:132)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.ActivityThread.main(ActivityThread.java:4123)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at java.lang.reflect.Method.invokeNative(Native Method)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at java.lang.reflect.Method.invoke(Method.java:491)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at dalvik.system.NativeStart.main(Native Method)
03-04 18:28:43.805: E/AndroidRuntime(19417): Caused by: java.lang.NullPointerException
03-04 18:28:43.805: E/AndroidRuntime(19417):    at ph.com.example.Project.MainActivity.get_Territory(MainActivity.java:169)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at ph.com.example.Project.MainActivity.onCreate(MainActivity.java:74)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1050)
03-04 18:28:43.805: E/AndroidRuntime(19417):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)

这是我获取领土的方法：

public void get_Territory() {
    String territory = String.valueOf(LoginActivity.g_territory);
    lbl_user.setText(LoginActivity.txt_username.getText().toString());
    String s = l_databaseHandler.get_territoryCode(territory);
    String f = l_databaseHandler.get_doctorFname(s);
    String l = l_databaseHandler.get_doctorLname(s);
    Cursor cursorAllDetails = l_databaseHandler.get_all_sameDoctorname(f, l);
    if (cursorAllDetails.getCount() != 0){
        fillData(cursorAllDetails);
    }else{
        save_territory();
    }
}

我在onCreate上以这种方式调用此方法：

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    l_databaseHandler = new DatabaseHandler(this);
    if (l_databaseHandler != null) {
        l_databaseHandler.close();
        l_databaseHandler.createDB();
    }
    Constants.from_add = false;
    Constants.from_edit = false;
    Constants.from_view = false;
    cast_views();
    get_Territory();
    log_out();
          }

任何帮助将不胜感激，谢谢。我以前会用这个，我以同样的方式再次使用它，我只是不明白为什么它会以这种方式行事。

Answer 1

像

这样

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(S_2nd_LoginActivity.this);
        alertDialogBuilder.setTitle("Are you sure you want to cancel?")
                          .setCancelable(false)
                          .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int id) {

                                finish();

                            }
                        })
                          .setNegativeButton("No", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                dialog.dismiss();
                            }
                          });
        AlertDialog alertDialog = alertDialogBuilder.create();
        alertDialog.show();

在您的onDestroy()方法中调用android.os.Process.killProcess(android.os.Process.myPid());

Answer 2

EditText txt_username;
TextView lbl_user;    
@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
txt_username= (EditText)findViewById(R.id.yourEditTextId);
lbl_user= (TextView )findViewById(R.id.yourTextViewId);

        l_databaseHandler = new DatabaseHandler(this);
        if (l_databaseHandler != null) {
            l_databaseHandler.close();
            l_databaseHandler.createDB();
        }
        Constants.from_add = false;
        Constants.from_edit = false;
        Constants.from_view = false;
        cast_views();
        get_Territory();
        log_out();
              }

Answer 3

尝试使用它。

String name = LoginActivity.txt_username.getText().toString();
if(name != null)
   lbl_user.setText(name);
else
   lbl_user.setText("");