Android入门：Intent入门(二)_Android

Android入门：Intent入门(2)

一、Intent与Activity应用

0.创建新的Activity步骤

在应用中创建新的Acitivity很常见；

步骤1：创建一个class继承Activity

步骤2：在Android-manifest.xml中添加<activity>元素

比如创建了一个名为SubActivity的Activity，则需要声明如下：

        <activity android:name=".SubActivity"></activity>

1.最简单的跳转到新的Activity

程序描述：MainActivity点击按钮后跳转到SubActivity，MainActivity传递一个（name,xiazdong）给SubActivity，并获得显示；

效果如下：

点击按钮后：

IntentActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class IntentActivity extends Activity {	private Button btn1;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        btn1 = (Button)this.findViewById(R.id.brn1);        btn1.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				Intent intent = new Intent();				intent.setClass(IntentActivity.this, SubActivity.class);  //从IntentActivity跳转到SubActivity				intent.putExtra("name", "xiazdong");  //放入数据				startActivity(intent);  //开始跳转			}		});    }}

SubActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.TextView;public class SubActivity extends Activity{	private TextView tv1;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		this.setContentView(R.layout.sub);		tv1 = (TextView)this.findViewById(R.id.tv1);		Intent intent = this.getIntent();    //获得当前的Intent 		Bundle bundle = intent.getExtras();  //获得全部数据		String value = bundle.getString("name");  //获得名为name的值		tv1.setText(value);	}}

2.带返回值的跳转

跳转到新的Activity并在结束后将返回值传给原Activity

程序描述：MainActivity跳转到SubActivity后，SubActivity执行完后返回一个结果码给IntentActivity，执行对应的过程；

程序效果：

点击跳转后执行完第二个Activity后再跳回第一个Activity

IntentActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class IntentActivity extends Activity {	private Button btn1;	private TextView tv1;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        btn1 = (Button)this.findViewById(R.id.brn1);        tv1 = (TextView)this.findViewById(R.id.tv2);        btn1.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				Intent intent = new Intent();				intent.setClass(IntentActivity.this, SubActivity.class);				startActivityForResult(intent, 100); //requestcode=100							}		});    }	@Override	protected void onActivityResult(int requestCode, int resultCode, Intent data) {		super.onActivityResult(requestCode, resultCode, data);		if(requestCode==100&&resultCode==200){			Bundle bundle = data.getExtras();			String response = bundle.getString("response");			tv1.setText(response);		}	}    }

SubActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.TextView;public class SubActivity extends Activity{	private TextView tv1;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		this.setContentView(R.layout.sub);		tv1 = (TextView)this.findViewById(R.id.tv1);		Intent intent = new Intent();  //创建一个Intent		intent.putExtra("response", "来自2");		setResult(200,intent);  //返回码为200		finish();	}}