android - 活动 B 到活动 A 的额外费用

Question

我有两个活动。在 Activity AI 中有Textview. EditText单击此按钮后，我使用.转到活动 B。

如何将EditText活动 B 中的值传递回TextView活动 A，同时在流程中保持活动 A 的原始状态？

Answer 1

像这样写活动A

public class MainActivity extends Activity {  
TextView textView1;  
Button button1;  
@Override  
protected void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);  
    setContentView(R.layout.activity_main);  
    textView1=(TextView)findViewById(R.id.textView1);  
    button1=(Button)findViewById(R.id.button1);  
    button1.setOnClickListener(new OnClickListener() {  
        @Override  
        public void onClick(View arg0) {  
            Intent intent=new Intent(MainActivity.this,SecondActivity.class);  
            startActivityForResult(intent, 2);// Activity is started with requestCode 2  
        }  
    });  
}  
// Call Back method  to get the Message form other Activity  
@Override  
   protected void onActivityResult(int requestCode, int resultCode, Intent data)  
   {  
             super.onActivityResult(requestCode, resultCode, data);  
              // check if the request code is same as what is passed  here it is 2  
               if(requestCode==2)  
                     {  
                        String message=data.getStringExtra("MESSAGE");   
                        textView1.setText(message);  
                     }  
 }  
 }

安装 startActivity 使用startActivityForResult

Intent intent=new Intent(MainActivity.this,SecondActivity.class);  
        startActivityForResult(intent, 2);// Activity is started with requestCode 2  

在活动 B 中设置这样的结果

   Intent intent=new Intent();  
                intent.putExtra("MESSAGE",message);  
                setResult(2,intent);  
                finish();//finishing activity  

你可以intent.putExtra("MESSAGE",message);参加活动 A( onActivityResult)