短信备份: 

• 代码实现过程 
  • 提供内容解析者把短信数据取出来

Uri uri = Uri.parse("content://sms/");            Cursor cursor = getContentResolver().query(uri, new String[]{"address", "body", "date"}, null, null, null);            Log.e(TAG, "backup: " + (cursor == null));

 

• • 使用xml序列化把数据保存到xml文件中

public class MainActivity extends AppCompatActivity {    private static final String TAG = "MainActivity";    private Button backup;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        backup = findViewById(R.id.backup);        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED) {            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_SMS}, 1);        } else {        }        backup.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                backup();            }        });    }    private void backup() {        try {            XmlSerializer xmlSerializer = Xml.newSerializer();            File file = new File(getFilesDir().getAbsolutePath(), "smsbackup.xml");            Log.e(TAG, "backup: " + getFilesDir().getAbsolutePath());            FileOutputStream fos = new FileOutputStream(file);            xmlSerializer.setOutput(fos, "utf-8");            xmlSerializer.startDocument("utf-8", true);            xmlSerializer.startTag(null, "smss");            Uri uri = Uri.parse("content://sms/");            Cursor cursor = getContentResolver().query(uri, new String[]{"address", "body", "date"}, null, null, null);            Log.e(TAG, "backup: " + (cursor == null));            while (cursor.moveToNext()) {                xmlSerializer.startTag(null, "sms");                xmlSerializer.startTag(null, "address");                Log.e(TAG, "backup: " + cursor.getString(0));                if (cursor.getString(0) == null || cursor.getString(0).equals("") || cursor.getString(0).equals(null)) {                    xmlSerializer.text("");                } else {                    xmlSerializer.text(cursor.getString(0));                }                xmlSerializer.endTag(null, "address");                xmlSerializer.startTag(null, "body");                Log.e(TAG, "backup: " + cursor.getString(1));                if (cursor.getString(1) == null || cursor.getString(1).equals("") || cursor.getString(1).equals(null)) {                    xmlSerializer.text("");                } else {                    xmlSerializer.text(cursor.getString(1));                }                xmlSerializer.endTag(null, "body");                xmlSerializer.startTag(null, "date");                Log.e(TAG, "backup: " + cursor.getString(2));                if (cursor.getString(2) == null || cursor.getString(2).equals("") || cursor.getString(2).equals(null)) {                    xmlSerializer.text("");                } else {                    xmlSerializer.text(cursor.getString(2));                }                xmlSerializer.endTag(null, "date");                xmlSerializer.endTag(null, "sms");                Log.e(TAG, "backup: 2222");            }            Log.e(TAG, "backup: 3333");            xmlSerializer.endTag(null, "smss");            xmlSerializer.endDocument();            Toast.makeText(this, "备份成功", Toast.LENGTH_SHORT).show();        } catch (Exception e) {            Log.e(TAG, "backup: " + e.getLocalizedMessage().toString());            Toast.makeText(this, "备份失败", Toast.LENGTH_SHORT).show();            e.printStackTrace();        }    }}