第七章

Uri 实例如下

content://com.android.contacts/data/phones
content://com.example.app.provider/table1

查询Query 方法参数解析:

Cursor cursor = getContentResolver().query(uri, projection, selection, selectionArgs,sortOrder);

新增数据方法如下:

ContentValues values = new ContentValues();
values.put("column1", "text");
values.put("column2", 1);
getContentResolver().insert(uri, values);

插入数据方法如下:

ContentValues values = new ContentValues();
values.put("column1", "");
getContentResolver().update(uri, values, "column1 = ? and column2 = ?", new
String[] {"text", "1"});

删除数据方法如下:

getContentResolver().delete(uri, "column2 = ?", new String[] { "1" });

读取联系人信息:

MainActivity.java 

package com.example.contactstest;
...
public class MainActivity extends AppCompatActivity {
    ArrayAdapter<String> adapter;
    List<String> contactsList = new ArrayList<>();
    private static final String TAG = "MainActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView contactsView = (ListView) findViewById(R.id.contacts_view);
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, contactsList);
        contactsView.setAdapter(adapter);
        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 {
            // 查询联系人数据
            Log.d(TAG, "CONTENT_URI: " + ContactsContract.CommonDataKinds.Phone.CONTENT_URI);
            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));
                    Log.d(TAG, "displayName: " + displayName);
                    // 获取联系人手机号
                    String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                    Log.d(TAG, "number: " + 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, String[] permissions,int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, 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:
        }
    }
}

在 AndroidManifest.xml 中注册  READ_CONTACTS  权限:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools">
    <uses-permission android:name="android.permission.READ_CONTACTS" />
    <application
　　　　　...
        <activity
            ...
        </activity>
    </application>
</manifest>

activity_main.xml 代码如下:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <ListView
        android:id="@+id/contacts_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </ListView>
</LinearLayout>