startActivityForResult案例

Info:startActivty 与 startActivityForResult区别

(1):startActivity 启动了其他Activity之后不会再回调过来，此时启动者与被启动者在启动后没有联系了。

(2):startActivityForResult 可以进行回调，之后有联系。

1:activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<TextView
android:id="@+id/tv_show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<Button
android:id="@+id/btn_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="button1"
android:layout_below="@id/tv_show"/>
</RelativeLayout>

2:MainActivity.java

public class MainActivity extends Activity {
    private Button btn1=null;
    private TextView tvShow=null;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn1=(Button)findViewById(R.id.btn_1);
        
        btn1.setOnClickListener(new OnClickListener(){
            public void onClick(View view){
                Intent intent=new Intent(MainActivity.this,OtherActivity.class);
                startActivityForResult(intent,100);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        
        if(requestCode==100 && resultCode==Activity.RESULT_OK){
            String info=data.getExtras().getString("info");
            tvShow=(TextView)findViewById(R.id.tv_show);
            tvShow.setText(info);
        }
    }
}

3:activity_other.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">

<EditText
android:id="@+id/et_input"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="input info"/>

<Button
android:id="@+id/btn_back"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button Back"
android:layout_below="@id/et_input"/>
</RelativeLayout>

4:OtherActivity.java

public class OtherActivity extends Activity {
    private EditText etInfo=null;
    private Button btnBack=null;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_other);
        
        etInfo=(EditText)findViewById(R.id.et_input);
        btnBack=(Button)findViewById(R.id.btn_back);
    
        btnBack.setOnClickListener(new OnClickListener(){
            public void onClick(View view){
                Intent intent=new Intent();
                String info=etInfo.getText().toString();
                intent.putExtra("info", info);
                
                setResult(Activity.RESULT_OK,intent);
                finish();    //关闭当前的Activity
            }
        });
    }
}