Question

例如，说我只有一个按钮。使用这样的XML：

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/PandR"
    android:id="@+id/PandRA">

我想在Java中做的是创建一个可以在另一个活动或Java类上访问的字符串值。这是我的Java目前的样子：

公共类TeamAOffense扩展了ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_team_aoffense);
    Toast.makeText(this, "Team A's turn.", Toast.LENGTH_LONG).show();

    // Make a method that saves a value for pressing PandRA, later used in CalcForAOffBDef

    // Button for PandRA, assigning value for calculating.
    final Button pandrBttn = (Button) findViewById(R.id.PandRA);

    pandrBttn.setOnClickListener(new View.OnClickListener() {

        // Needs to save value that is later compared.

        @Override
        public void onClick(View v) {
            Intent intent = new Intent(TeamAOffense.this, ExchangeAToB.class);
            startActivity(intent);
        }
    });

    // Button for MandFA, assigning value for calculating.
    final Button mandfBttn = (Button) findViewById(R.id.MandFA);

    mandfBttn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // Needs to save value that is later compared.
            Intent intent = new Intent(TeamAOffense.this, ExchangeAToB.class);
            startActivity(intent);
        }
    });

    // Button for SandCA, assigning value for calculating.
    final Button sandcBttn = (Button) findViewById(R.id.SandCA);

    sandcBttn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // Needs to save value that is later compared.
            Intent intent = new Intent(TeamAOffense.this, ExchangeAToB.class);
            startActivity(intent);
        }
    });
}

Answer 1

您有两种方式：

使用Intent.putExtra(String key, String value)
使用singleton传递Objects或String甚至是custom class

<强>实施例：
例1

 Intent intent =  new Intent(TeamAOffense.this, ExchangeAToB.class);
 intent.putExtra("KEY", "Value");
 startActivity(intent);
 // and in `ExchangeAToB` class use 
 String key getIntent().getExtras().getString("KEY");`

示例2

public class MyInstance{
private static MyInstance instance = null;
private Object mObject;
private MyInstance(){
mObject = new Object();
}

public static MyInstance getInstance(){
if(instance == null){
instance = new MyInstance();
}
return instance;
}

public Object getObject(){
return mObject;
}

public void setObject(Object obj){
mObject = obj;
}
}
// Use MyInstance.getInstance().setObject(new String()); // in activity 1
// and Object myObject = MyInstance.getInstance().getObject(); // in activity 2

**使用后不要忘记清除对象

（Android / Java）如何在活动或java类中分配字符串和共享？

1 个答案: