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();
}
}