跨程序共享数据，跨进程共享数据

读取联系人信息

1.定义ListView

2.声明权限AndroidManifest.xml

3.处理数据获取与展示

package demo.jq.com.contactstest;import android.content.pm.PackageManager;import android.database.Cursor;import android.provider.ContactsContract;import android.support.annotation.NonNull;import android.support.v4.app.ActivityCompat;import android.support.v4.content.ContextCompat;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListView;import android.widget.Toast;import java.util.ArrayList;import java.util.List;import java.util.jar.Manifest;/** * @author Jim */public class MainActivity extends AppCompatActivity {    /**     * 定义adapter     */    ArrayAdapter
    
      adapter;    List
     
       contactsList = new ArrayList<>();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // 初始化ListView对象        ListView contactsView = (ListView) findViewById(R.id.contacts_view);        // 初始化adapter        adapter = new ArrayAdapter
      
       (this,android.R.layout.simple_list_item_1,contactsList);        // 设置listview的适配内容        contactsView.setAdapter(adapter);        if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {            // 设置权限可读            ActivityCompat.requestPermissions(this,new String[]{android.Manifest.permission.READ_CONTACTS},1);        } else {            // 读取联系人信息            readContacts();        }    }    private void readContacts() {        Cursor cursor = null;        try {            // 查询联系人数据            cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,null);            if (cursor != null) {                while (cursor.moveToNext()) {                    // 获取联系人姓名                    String displayName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));                    // 获取手机号                    String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));                    contactsList.add(displayName + "\n" + number);                }                adapter.notifyDataSetChanged();            }        } catch (Exception e) {            e.printStackTrace();        } finally {            if (cursor != null) {                cursor.close();            }        }    }    @Override    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, int[] grantResults) {        switch (requestCode) {            case 1:                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {                    readContacts();                } else {                    Toast.makeText(this,"You denied the permission",Toast.LENGTH_SHORT).show();                }                break;            default:        }    }}