Android组件——内容提供者ContentResolver

内容提供者
整体来说内容提供者就相当于别的应用提供了一个数据供你访问，比如访问短信，就是使用的内容提供者

public class readsms extends AppCompatActivity {

    private TextView textView;
    private Button sms;
    String text;
    Handler handler=new Handler(){
        @Override
        public void handleMessage(@NonNull Message msg) {
            super.handleMessage(msg);
            textView.setText(((String)msg.obj));
        }
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_readsms);
        textView = findViewById(R.id.smstext);
        sms = findViewById(R.id.sms);
        sms.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                read();


            }
        });
    }


    public  void read()
    {
        Uri uri=Uri.parse("content://sms/");
        ContentResolver resolver = getContentResolver();
        Cursor cursor = resolver.query(uri, new String[]{"_id", "address", "type", "body", "date"}, null, null, null);
        List<smsinfo> smsinfos=new ArrayList<>();
        if(cursor!=null && cursor.getCount()>0)
        {
            while (cursor.moveToNext())
            {
                int id=cursor.getInt(0);
                String address=cursor.getString(1);
                int type=cursor.getInt(2);
                String body=cursor.getString(3);
                long date=cursor.getLong(4);
                smsinfo smsinfo=new smsinfo(id,address,type,body,date);
                smsinfos.add(smsinfo);


            }
            cursor.close();
        }

   text="手机号码"+smsinfos.get(1).getAddress()+"\n";
       text="短信内容"+smsinfos.get(1).getBody()+"\n";
       Message message=new Message();
       message.obj=text;
       handler.sendMessage(message);

    }

    }

不难看出
1.先创建ContentResolver对象，同时指定Uri接口，注意是Uri不是Url

 Uri uri=Uri.parse("content://sms/");
        ContentResolver resolver = getContentResolver();

短信提供了一个SQLlist数据库

 Cursor cursor = resolver.query(uri, new String[]{"_id", "address", "type", "body", "date"}, null, null, null);

因此这样接收但是别忘了，任何东西都要封装为一个对象