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
             }
         });
     }
 }