Intent的Component，Action和Category属性详解-android学习之旅（五十）

Component属性

代码示例

public class MainActivity extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.btnIntent).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ComponentName name = new ComponentName(MainActivity.this,MainActivity2.class);
Intent intent = new Intent();
intent.setComponent(name);
startActivity(intent);
}
});
}

Action和Category属性以及IntentFilter配置

代码示例

public class MainActivity extends Activity{
public  final static String LIUPENG_ACTION ="liu.intent.action.liuaction";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.btnIntent).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent();
intent.setAction(MainActivity.LIUPENG_ACTION);
startActivity(intent);
}
});
}
}

<activity
android:name=".MainActivity2"
android:label="@string/title_activity_main_activity2" >
<intent-filter>
<action android:name="liu.intent.action.liuaction"/>
<category android:name="android.intent.category.DEFAULT"/>
</intent-filter>
</activity>

系统的Action和Category介绍

察看并获取系统联系人数据demo

public class MainActivity extends Activity{
final int PICK_CONTACT = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.btnContacts).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent();
intent.setAction(Intent.ACTION_GET_CONTENT);
intent.setType("vnd.android.cursor.item/phone");
startActivityForResult(intent,PICK_CONTACT);
}
});
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == PICK_CONTACT && resultCode == RESULT_OK){
Uri contactsData = data.getData();
CursorLoader cursorLoader = new CursorLoader(this,contactsData,null,null,null,null);
Cursor cursor = cursorLoader.loadInBackground();
if (cursor.moveToFirst()){
String contactId = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));
String name = cursor.getString(cursor.getColumnIndexOrThrow(ContactsContract.Contacts.DISPLAY_NAME));
String phoneNumber = "此联系人暂未输入号码";
Cursor phones = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,ContactsContract.CommonDataKinds.Phone.CONTACT_ID+"="+contactId,null,null);
if (phones.moveToFirst()){
phoneNumber = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
}
phones.close();
((EditText)findViewById(R.id.show)).setText(name);
((EditText)findViewById(R.id.phone)).setText(phoneNumber);
}
cursor.close();
}
}
}

布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical"
>
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/show"
android:editable="false"
android:cursorVisible="false"/>
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/phone"
android:editable="false"
android:cursorVisible="false"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btnContacts"
android:text="察看联系人"/>

</LinearLayout>

返回Home桌面demo

public class MainActivity extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.btnContacts).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
startActivity(intent);
}
});
}
}