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(); } }