android studio 写一个简单的内容提供者代码模板

好的，以下是一个简单的内容提供者代码模板：

public class MyContentProvider extends ContentProvider {

    // 定义常量，用于 UriMatcher 匹配 Uri
    private static final int TABLE1 = 1;
    private static final int TABLE1_ID = 2;

    // 定义 UriMatcher
    private static final UriMatcher sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

    static {
        sUriMatcher.addURI("com.example.myapp.provider", "table1", TABLE1); // 匹配整张表
        sUriMatcher.addURI("com.example.myapp.provider", "table1/#", TABLE1_ID); // 匹配表中某条记录，# 表示数字
    }

    // 定义数据库帮助类
    private MyDatabaseHelper mDatabaseHelper;

    @Override
    public boolean onCreate() {
        mDatabaseHelper = new MyDatabaseHelper(getContext(), "myapp.db", null, 1);
        return true;
    }

    @Nullable
    @Override
    public Cursor query(@NonNull Uri uri, @Nullable String[] projection, @Nullable String selection, @Nullable String[] selectionArgs, @Nullable String sortOrder) {
        SQLiteDatabase db = mDatabaseHelper.getReadableDatabase();
        Cursor cursor = null;
        switch (sUriMatcher.match(uri)) {
            case TABLE1:
                cursor = db.query("table1", projection, selection, selectionArgs, null, null, sortOrder);
                break;
            case TABLE1_ID:
                String id = uri.getPathSegments().get(1);
                cursor = db.query("table1", projection, "id=?", new String[]{id}, null, null, sortOrder);
                break;
            default:
                throw new IllegalArgumentException("Unknown Uri: " + uri);
        }
        return cursor;
    }

    @Nullable
    @Override
    public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) {
        SQLiteDatabase db = mDatabaseHelper.getWritableDatabase();
        Uri returnUri = null;
        switch (sUriMatcher.match(uri)) {
            case TABLE1:
                long id = db.insert("table1", null, values);
                returnUri = ContentUris.withAppendedId(uri, id);
                break;
            default:
                throw new IllegalArgumentException("Unknown Uri: " + uri);
        }
        return returnUri;
    }

    @Override
    public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String selection, @Nullable String[] selectionArgs) {
        SQLiteDatabase db = mDatabaseHelper.getWritableDatabase();
        int count = 0;
        switch (sUriMatcher.match(uri)) {
            case TABLE1:
                count = db.update("table1", values, selection, selectionArgs);
                break;
            case TABLE1_ID:
                String id = uri.getPathSegments().get(1);
                count = db.update("table1", values, "id=?", new String[]{id});
                break;
            default:
                throw new IllegalArgumentException("Unknown Uri: " + uri);
        }
        return count;
    }

    @Override
    public int delete(@NonNull Uri uri, @Nullable String selection, @Nullable String[] selectionArgs) {
        SQLiteDatabase db = mDatabaseHelper.getWritableDatabase();
        int count = 0;
        switch (sUriMatcher.match(uri)) {
            case TABLE1:
                count = db.delete("table1", selection, selectionArgs);
                break;
            case TABLE1_ID:
                String id = uri.getPathSegments().get(1);
                count = db.delete("table1", "id=?", new String[]{id});
                break;
            default:
                throw new IllegalArgumentException("Unknown Uri: " + uri);
        }
        return count;
    }

    @Nullable
    @Override
    public String getType(@NonNull Uri uri) {
        switch (sUriMatcher.match(uri)) {
            case TABLE1:
                return "vnd.android.cursor.dir/table1";
            case TABLE1_ID:
                return "vnd.android.cursor.item/table1";
            default:
                throw new IllegalArgumentException("Unknown Uri: " + uri);
        }
    }
}

其中，`com.example.myapp.provider` 是你自己定义的内容提供者的 authority，你需要将其替换为你自己的 authority。`table1` 是你自己定义的表名，你需要将其替换为你自己的表名。在实际使用中，你还需要根据自己的需求对代码进行调整。