使用指定的Action，Category调用系统Activi

Android提供了大量的标准Action，Category：

例子，查看并获取联系人电话

用户点击按钮值会显示系统的联系人列表，当用户单击联系人之后，程序将会显示该联系人的名字和电话

MainActivity.java

package com.hust.getcontacts;

import android.app.Activity;
import android.content.CursorLoader;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;


public class MainActivity extends Activity {
    
	final int PICK_CONTACT=0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn=(Button) findViewById(R.id.button1);
        
        btn.setOnClickListener(new OnClickListener(){

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				//创建intent
				Intent intent=new Intent();
				//设置Intent的Action属性
				intent.setAction(Intent.ACTION_GET_CONTENT);
				//设置Intent的Type属性
				intent.setType("vnd.android.cursor.item/phone");
				//启动Activity，并希望获取该Activity的结果
				startActivityForResult(intent,PICK_CONTACT);
			}        	
        });       
        
    }
    
//重写该方法，处理返回的联系人数据在参数Intent data中
    @Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		// TODO Auto-generated method stub
		super.onActivityResult(requestCode, resultCode, data);
		switch(requestCode)
		{
		 case (PICK_CONTACT):
			  if(resultCode==Activity.RESULT_OK){//Activity.RESULT_OK标准Activity结果 -1
				  //获取返回的联系人数据
				  Uri contactdata=data.getData();
				  CursorLoader cursorloader=new CursorLoader(this, contactdata, null, null, null, null);
				  //查询联系人信息表
				  Cursor cursor=cursorloader.loadInBackground();
				  //如果查询到指定的联系人
				  if(cursor.moveToFirst()){
					 //获取联系人的Id
					  String contactId=cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));
					  //获取联系人的名字
					  String name=cursor.getString(cursor.getColumnIndexOrThrow(ContactsContract.Contacts.DISPLAY_NAME));
				      String phoneNumber="此联系人暂未输入电话号码";
				      
				      //根据联系人查询该联系人的详细信息
				      Cursor phones=getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, ContactsContract.CommonDataKinds.Phone.CONTACT_ID+"="+contactId, null, null);
				     //
				      if(phones.moveToFirst()){
				    	  //取出电话号码
				    	  phoneNumber=phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
				      }
				      phones.close();
				      
				      EditText show=(EditText) findViewById(R.id.editText1);
				      show.setText(name);
				      EditText phone=(EditText) findViewById(R.id.editText2);
				      phone.setText(phoneNumber);
				      
				  }
				  cursor.close();
			  }
		        break;
			
		
		}
	}


	@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}