Java / Android：傳遞Intent Extras，然后將其用於其他方法

Question

大家好，
這次，我對Intent＆Extras有疑問。

這是我的第一次活動

Intent i1 = new Intent(RoomSetting.this, App.class);
i1.putExtra("subposition1", "right");
final int result=1;
startActivityForResult(i1, result);

在第二個活動中，我嘗試獲取“ subposition1”值

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccVals = new Number3d(); 
    Bundle extras = getIntent().getExtras();
    String SubPos = extras.getString("subposition1");
}

我的問題是，如何在其他方法上使用SubPos？

很抱歉提出這個問題。 提前致謝

Answer 1

String SubPos;
// declare SubPos String as class variable and you can access anywhere in class<<<
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccVals = new Number3d(); 
    Bundle extras = getIntent().getExtras();
    SubPos = extras.getString("subposition1");
}

public void anotherMethod(){
//here you can access it...
}

Answer 2

在onCreate之前聲明SubPos為：

public String SubPos=null; // or you can also declare it as static as your need
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccVals = new Number3d(); 
    Bundle extras = getIntent().getExtras();
    SubPos = extras.getString("subposition1");
}


   public void testmethod()
   {
      String str=SubPos; //get SubPos value  
    }

Answer 3

有兩種輕松實現的方式：

第一種方式：對類使用全局變量：

   String SubPos;
   public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccVals = new Number3d(); 
    Bundle extras = getIntent().getExtras();
    SubPos = extras.getString("subposition1"); //note that I've deleted the 'String'
}

2n方式：將變量傳遞給方法：

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccVals = new Number3d(); 
    Bundle extras = getIntent().getExtras();
    String SubPos = extras.getString("subposition1");
    otherMethod(SubPos);
}

public void otherMethod(String s) {
    //do stuff.
}

我考慮過，也許您想在另一個類中使用此變量，然后可以添加此函數（在該類中將String SubPos設置為全局）：

   String SubPos;
   public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mAccVals = new Number3d(); 
    Bundle extras = getIntent().getExtras();
    SubPos = extras.getString("subposition1"); //note that I've deleted the 'String'
   }
    public String getSubPos() {
        return SubPos;
    }

這樣，您可以在具有該實例的任何其他類中調用instanceOfTheClass.getSubPos（）。

Answer 4

更換

Bundle extras = getIntent().getExtras();
String SubPos = extras.getString("subposition1");

與

String SubPos = getIntent().getStringExtra("subposition1");

Answer 5

只需在您的“其他方法”上調用它即可。

String subposition = getIntent().getStringExtra("subposition1");