Question

我创建了一个应用程序。在这个应用程序中，我想使用Getter和Setter方法从数据库中获取数据。我不知道我该怎么做。请帮我。必要的代码在这里：

DisplayMedia.java

public class DisplayMedia extends Activity {
    ImageView displayImage;
    VideoView displayVideo;
    TextView txtMediaDate,txtMediaTime,txtMediaAddress;
    DatabaseHelper dbHelper;

    Intent intent;

    String mediaPath,mediaDate,mediaTime,mediaAddress;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.display_media);

        displayImage = (ImageView) findViewById(R.id.displayImage);
        displayVideo = (VideoView) findViewById(R.id.displayVideo);

        txtMediaDate = (TextView) findViewById(R.id.txtMediaDate);
        txtMediaTime = (TextView) findViewById(R.id.txtMediaTime);
        txtMediaAddress = (TextView) findViewById(R.id.txtMediaAddress);


        dbHelper = new DatabaseHelper(getApplicationContext());
        mediaPath = dbHelper.displayImages();
        File mediaFile = new File(mediaPath);

        if (mediaFile.exists()) {

            if (isImage(mediaPath)) {
                displayVideo.setVisibility(View.GONE);
                displayImage.setVisibility(View.VISIBLE);
                Bitmap myBitmap = BitmapFactory.decodeFile(mediaFile.getAbsolutePath());
                int height = (myBitmap.getHeight() * 512 / myBitmap.getWidth());
                Bitmap scale = Bitmap.createScaledBitmap(myBitmap, 512, height, true);
                displayImage.setImageBitmap(scale);
            } else {
                displayImage.setVisibility(View.GONE);
                displayVideo.setVisibility(View.VISIBLE);

                displayVideo.setVideoURI(Uri.parse(mediaFile.toString()));
                displayVideo.start();
            }
        }
    }       

    public static boolean isImage(String str) {
        boolean temp = false;
        String[] arr = { ".jpeg", ".jpg", ".png", ".bmp", ".gif" };
        for (int i = 0; i < arr.length; i++) {
            temp = str.endsWith(arr[i]);
            if (temp) {
                break;
            }
        }
        return temp;
    }

}

DataBaseHelper.java

public void insertMedia(String mPath,String mDate,String mTime,String mAddress) {
        db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        cur = db.query(INCIDENT, null, null, null, null, null, null);
        cur.moveToFirst();

        values.put("mediaPath", mPath);
        values.put("mediaDate", mDate);
        values.put("mediaTime", mTime);
        values.put("mediaAddress", mAddress);

        db.insert(INCIDENT, null, values);
        db.close();

    }

    public String displayMedia() {
        db = this.getReadableDatabase();
        cur = db.query(INCIDENT, null, null, null, null, null, null);
        String path = null,date = null, time = null, address = null;
        cur.moveToFirst();
        while (cur.isAfterLast() == false) {
            path = (cur.getString(0));
            date = (cur.getString(1));
            time = (cur.getString(2));
            address = (cur.getString(3));

            cur.moveToNext();

        }
        return path;
    }

在这个应用程序中，我成功地在数据库中插入了数据。在我的数据库中，以下数据已存储：

MediaPath, MediaDate, MediaTime, MediaAddress

现在我想使用上面displayMedia()获取所有数据。我怎么能这样做？

Answer 1

你可以得到一个Cursor对象包含里面的所有表数据：

   public Cursor getCursor() {

    db = this.getReadableDatabase();

    return db.query(INCIDENT, null, null, null, null, null, null);
}

然后，无论您需要什么，您都可以获得以下信息：

  Cursor c = yourDatabaseClass.getCursor();
  int rows = c.getCount();
  for(int i=0;i<rows;i++){

    String path = c.getString(0);
    String date = c.getString(1);
    String time = c.getString(2);
    String adress = c.getString(3);

  c.moveToNext();

  }

然后由您决定如何显示路径/日期/时间/地址信息。

从数据库获取数据。使用Getters＆amp;塞特斯方法......！

1 个答案: