Activity间中使用Intent传值

主页面用来输入一个值传入第二个页面显示,关闭第二个页面返回一个值

主页布局:

<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"
tools:context=".MainActivity" > <TextView
android:id="@+id/view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="关闭第二个页面后返回值" /> <EditText
android:id="@+id/txt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/view"
android:text="" />
<Button
android:id="@+id/btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/txt"
android:text="转第二页" />
</RelativeLayout>

MainActivity,主要通过startActivityForResult来传递请求码,返回数据的时候,第二个页面调用Activity.setResult()方法设置返回Intent以及返回码,需要重写源Activity的onActivityResult()方法以便于接受返回的Intent,在onActivityResult()中会判断请求码和响应码

package com.example.android01;

import android.os.Bundle;
import android.R.string;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast; public class MainActivity extends Activity { private final static String TAG="MainActivity";
private final static int REQUEST_CODE = 1;
private final static String CONTENT = "content";
private EditText txtEditText = null;
private Button btnButton = null; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtEditText = (EditText) this.findViewById(R.id.txt);
if (savedInstanceState != null && savedInstanceState.containsKey(CONTENT)) {
txtEditText.setText(savedInstanceState.getString(CONTENT) + "[2]");
}
btnButton = (Button) this.findViewById(R.id.btn);
btnButton.setOnClickListener(new OnClickListener() { @Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
String str=txtEditText.getText().toString();
intent.putExtra("fromMain", str);
// startActivity(intent);
// 启动需要监听返回值的Activity,并设置请求码:requestCode
startActivityForResult(intent, REQUEST_CODE);
}
});
} /*
* (non-Javadoc)
*
* @see android.app.Activity#onActivityResult(int, int,
* android.content.Intent)
*/
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// 当otherActivity中返回数据的时候,会响应此方法
// requestCode和resultCode必须与请求startActivityForResult()和返回setResult()的时候传入的值一致。
if (requestCode == REQUEST_CODE && resultCode == SecondActivity.RESULT_CODE) {
Bundle bundle=data.getExtras();
String strResult = bundle.getString("result");
Log.i(TAG,"onActivityResult: "+ strResult);
Toast.makeText(MainActivity.this, strResult, Toast.LENGTH_LONG).show();
}
} /*
* (non-Javadoc) 保存Activity页面状态在onStop之前执行
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
// TODO Auto-generated method stub
super.onSaveInstanceState(outState);
String contentString = txtEditText.getText().toString();
outState.putString(CONTENT, contentString);
} /*
* (non-Javadoc)
*
* @see android.app.Activity#onCreateOptionsMenu(android.view.Menu)
*/
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
} }

每二个Activity

/**
*
*/
package com.example.android01; import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView; /**
* @author Administrator 2014-3-12 下午10:21:17
*/
public class SecondActivity extends Activity { private final static String TAG="MainActivity";
public final static int RESULT_CODE=1;
private Button btnBack = null;
private EditText txtContent = null;
private TextView viewContent = null; /*
* (non-Javadoc)
*
* @see android.app.Activity#onCreate(android.os.Bundle)
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.secondactivity); txtContent = (EditText) this.findViewById(R.id.txtContent);
viewContent = (TextView) this.findViewById(R.id.viewContent);
btnBack = (Button) this.findViewById(R.id.btnBack); Intent intent = getIntent();
Bundle bundle = intent.getExtras();
String strContentString = bundle.getString("fromMain");
Log.i(TAG,"SecondActivity: "+ strContentString);
viewContent.setText(strContentString);
btnBack.setOnClickListener(new OnClickListener() { @Override
public void onClick(View arg0) {
Intent intent = new Intent();
intent.putExtra("result", txtContent.getText().toString());
setResult(RESULT_CODE, intent);// 设置resultCode,onActivityResult()中能获取到
finish();
}
});
} }

注意请求码与返回码的对应判断,因为可能有多个请求码与返回码。

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