ContentProvider跨程序共享数据（二）

##读取联系人##
以读取联系人为例子，实战使用一下。

##activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ListView
        android:id="@+id/lv_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    </ListView>

</RelativeLayout>

---

##MainActivity##
里面使用了运行时权限的知识，如果不熟悉的话，点击我！

public class MainActivity extends AppCompatActivity {
    ArrayAdapter<String> adapter;
    List<String> lists = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView lv_list = (ListView) findViewById(R.id.lv_list);
        //创建设置适配器
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, lists);
        lv_list.setAdapter(adapter);
        //申请读取联系人权限
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, 1);
        } else {
            readContacts();
        }
    }

    private void readContacts() {
        Cursor cursor = null;
        try {
            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));
                    //获取联系人手机号
                    String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                    lists.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, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 1:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    readContacts();
                } else {
                    Toast.makeText(this, "取消授权", Toast.LENGTH_SHORT).show();
                }
                break;
            default:
                break;
        }
    }
}

读取联系人的权限也要去AndroidManifest.xml中声明

<uses-permission android:name="android.permission.READ_CONTACTS"/>

完结~