轻巧级记事本的开发

      今天按计划没什么大事，所以去学习制作了一下记事本，有三种功能，可以添加文字、图文、视频+文字，还有删除功能。

  首先看到MainActivity:

初始化界面

public void initView() {
    lv = (ListView) findViewById(R.id.list);
    textbtn = (Button) findViewById(R.id.text);
    imgbtn = (Button) findViewById(R.id.img);
    videobtn = (Button) findViewById(R.id.video);
    textbtn.setOnClickListener(this);
    imgbtn.setOnClickListener(this);
    videobtn.setOnClickListener(this);
    notesDB = new NoteDB(this);
    dbReader = notesDB.getReadableDatabase();
    lv.setOnItemClickListener(new OnItemClickListener() {

      @Override
      public void onItemClick(AdapterView<?> parent, View view,
          int position, long id) {
        cursor.moveToPosition(position);
        Intent i = new Intent(MainActivity.this, SelectAct.class);
        i.putExtra(NoteDB.ID,
            cursor.getInt(cursor.getColumnIndex(NoteDB.ID)));
        i.putExtra(NoteDB.CONTENT, cursor.getString(cursor
            .getColumnIndex(NoteDB.CONTENT)));
        i.putExtra(NoteDB.TIME,
            cursor.getString(cursor.getColumnIndex(NoteDB.TIME)));
        i.putExtra(NoteDB.PATH,
            cursor.getString(cursor.getColumnIndex(NoteDB.PATH)));
        i.putExtra(NoteDB.VIDEO,
            cursor.getString(cursor.getColumnIndex(NoteDB.VIDEO)));
        startActivity(i);
      }
    });
  }

三个按钮的点击，用1-3来表示三个按钮的响应code。

@Override
  public void onClick(View v) {
    i = new Intent(this, AddContent.class);
    switch (v.getId()) {
    case R.id.text:
      i.putExtra("flag", "1");
      startActivity(i);
      break;

    case R.id.img:
      i.putExtra("flag", "2");
      startActivity(i);
      break;

    case R.id.video:
      i.putExtra("flag", "3");
      startActivity(i);
      break;
    }
  }

在MyAdapter.java中，

获取文本内容：

public View getView(int position, View convertView, ViewGroup parent) {

    LayoutInflater inflater = LayoutInflater.from(context);
    layout = (LinearLayout) inflater.inflate(R.layout.cell, null);
    TextView contenttv = (TextView) layout.findViewById(R.id.list_content);
    TextView timetv = (TextView) layout.findViewById(R.id.list_time);
    ImageView imgiv = (ImageView) layout.findViewById(R.id.list_img);
    ImageView videoiv = (ImageView) layout.findViewById(R.id.list_video);
    cursor.moveToPosition(position);
    String content = cursor.getString(cursor.getColumnIndex("content"));
    String time = cursor.getString(cursor.getColumnIndex("time"));
    String url = cursor.getString(cursor.getColumnIndex("path"));
    String urlvideo = cursor.getString(cursor.getColumnIndex("video"));
    contenttv.setText(content);
    timetv.setText(time);
    videoiv.setImageBitmap(getVideoThumbnail(urlvideo, 200, 200,
        MediaStore.Images.Thumbnails.MICRO_KIND));
    imgiv.setImageBitmap(getImageThumbnail(url, 200, 200));
    return layout;
  }

得到拍照后图片的缩略图

public Bitmap getImageThumbnail(String uri, int width, int height) {
    Bitmap bitmap = null;
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    bitmap = BitmapFactory.decodeFile(uri, options);
    options.inJustDecodeBounds = false;
    int beWidth = options.outWidth / width;
    int beHeight = options.outHeight / height;
    int be = 1;
    if (beWidth < beHeight) {
      be = beWidth;
    } else {
      be = beHeight;
    }
    if (be <= 0) {
      be = 1;
    }
    options.inSampleSize = be;
    bitmap = BitmapFactory.decodeFile(uri, options);
    bitmap = ThumbnailUtils.extractThumbnail(bitmap, width, height,
        ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
    return bitmap;
  }

得到摄像的视频的缩略图：

private Bitmap getVideoThumbnail(String uri, int width, int height, int kind) {
    Bitmap bitmap = null;
    bitmap = ThumbnailUtils.createVideoThumbnail(uri, kind);
    bitmap = ThumbnailUtils.extractThumbnail(bitmap, width, height,
        ThumbnailUtils.OPTIONS_RECYCLE_INPUT);

    return bitmap;
  }

在Select.java中：

删除功能：

if (getIntent().getStringExtra(NoteDB.PATH).equals("null")) {
      s_img.setVisibility(View.GONE);
    } else {
      s_img.setVisibility(View.VISIBLE);
    }
    if (getIntent().getStringExtra(NoteDB.VIDEO).equals("null")) {
      s_video.setVisibility(View.GONE);
    } else {
      s_video.setVisibility(View.VISIBLE);
    }

删除写的内容

public void deleteDate() {
    dbWriter.delete(NoteDB.TABLE_NAME,
        "_id=" + getIntent().getIntExtra(NoteDB.ID, 0), null);
  }

之后还有一些返回结果之内的东西，这里就不一一说明了，布局文件可以去看源码。记得在清单文件中添加权限哦！