使用指定的Action，Category调用系统Activity

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); } } ~~~