开发一款能够将手机短信存储到手机硬盘的app,需要了解手机操作系统的短信存储机制和相关的编程技术。
在Android操作系统中,短信存储在SQLite数据库中。开发者可以通过Android提供的Content Provider访问和操作短信数据库。Content Provider是Android中非常重要的一个组件,它允许应用程序访问其他应用程序的数据,并且提供了一种标准的方式来与其他应用程序共享数据。
首先,需要在AndroidManifest.xml文件中声明权限,以获取读取和写入短信的权限。
```xml
```
接下来,需要定义一个Content Provider,以便应用程序可以访问短信数据库。以下是一个简单的Content Provider示例:
```java
public class SmsContentProvider extends ContentProvider {
private static final String AUTHORITY = "com.example.myapp.smscontentprovider";
private static final String BASE_PATH = "sms";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + BASE_PATH);
private static final int SMS = 1;
private static final int SMS_ID = 2;
private static final UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static {
uriMatcher.addURI(AUTHORITY, BASE_PATH, SMS);
uriMatcher.addURI(AUTHORITY, BASE_PATH + "/#", SMS_ID);
}
private SmsDatabaseHelper dbHelper;
@Override
public boolean onCreate() {
dbHelper = new SmsDatabaseHelper(getContext());
return true;
}
@Nullable
@Override
public Cursor query(@NonNull Uri uri, @Nullable String[] projection, @Nullable String selection,
@Nullable String[] selectionArgs, @Nullable String sortOrder) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
Cursor cursor = null;
switch (uriMatcher.match(uri)) {
case SMS:
cursor = db.query(SmsDatabaseHelper.TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
break;
case SMS_ID:
selection = SmsDatabaseHelper._ID + "=?";
selectionArgs = new String[] { String.valueOf(ContentUris.parseId(uri)) };
cursor = db.query(SmsDatabaseHelper.TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
break;
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
@Nullable
@Override
public String getType(@NonNull Uri uri) {
switch (uriMatcher.match(uri)) {
case SMS:
return "vnd.android.cursor.dir/vnd.com.example.myapp.sms";
case SMS_ID:
return "vnd.android.cursor.item/vnd.com.example.myapp.sms";
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
}
@Nullable
@Override
public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
long id = db.insert(SmsDatabaseHelper.TABLE_NAME, null, values);
getContext().getContentResolver().notifyChange(uri, null);
return ContentUris.withAppendedId(uri, id);
}
@Override
public int delete(@NonNull Uri uri, @Nullable String selection, @Nullable String[] selectionArgs) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
int count = 0;
switch (uriMatcher.match(uri)) {
case SMS:
count = db.delete(SmsDatabaseHelper.TABLE_NAME, selection, selectionArgs);
break;
case SMS_ID:
selection = SmsDatabaseHelper._ID + "=?";
selectionArgs = new String[] { String.valueOf(ContentUris.parseId(uri)) };
count = db.delete(SmsDatabaseHelper.TABLE_NAME, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String selection,
@Nullable String[] selectionArgs) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
int count = 0;
switch (uriMatcher.match(uri)) {
case SMS:
count = db.update(SmsDatabaseHelper.TABLE_NAME, values, selection, selectionArgs);
break;
case SMS_ID:
selection = SmsDatabaseHelper._ID + "=?";
selectionArgs = new String[] { String.valueOf(ContentUris.parseId(uri)) };
count = db.update(SmsDatabaseHelper.TABLE_NAME, values, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Invalid URI: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
}
```
在上述示例中,我们定义了一个名为SmsContentProvider的Content Provider,它可以访问名为sms的表格。我们还定义了一些常量来描述Content Provider的URI和操作类型。在query、insert、delete和update方法中,我们可以执行相应的数据库操作,并在操作完成后通过ContentResolver的notifyChange方法通知系统数据已经发生了变化。
接下来,我们需要在应用程序中使用Content Provider来读取和写入短信。以下是一个简单的示例,演示了如何读取所有的短信,并将它们保存到一个文件中:
```java
public class MainActivity extends AppCompatActivity {
private static final String FILENAME = "sms.txt";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Uri uri = Uri.parse("content://sms");
Cursor cursor = getContentResolver().query(uri, null, null, null, null);
try {
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
while (cursor.moveToNext()) {
String address = cursor.getString(cursor.getColumnIndex("address"));
String body = cursor.getString(cursor.getColumnIndex("body"));
fos.write((address + ": " + body + "\n").getBytes());
}
fos.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
cursor.close();
}
}
}
```
在上述示例中,我们首先使用Content Resolver查询所有的短信。然后,我们将短信的内容写入一个文件中,每一条短信占一行。
总之,开发一个能够将手机短信存储到手机硬盘的app,需要了解Android操作系统的短信存储机制和Content Provider的使用方法。通过Content Provider,我们可以访问和操作短信数据库,并将短信的内容保存到文件中。