Android(安卓)ApiDemo 笔记（一）Content与Graphics

一.package com.example.android.apis.content;

1.ReadAsset:从asset目录里读出

2.ResourcesSample：在values的strings.xml里取得string,

以及在非activity里取得方法。

Resources res = context.getResources();
CharSequence cs = res.getText(R.string.styled_text);

3.StyledText:在TextView里直接setText带有styled的字符串<string name="styled_text">Plain, bold, italic, bold-italic</string>

二.package com.example.android.apis.graphics;

1.AlphaBitmap：应用Paint p.setAntiAlias(true);//抗锯齿，如果没有调用这个方法，写上去的字不饱满，不美观，看地不太清楚

下图为p.setAntiAlias(false)效果

下图为p.setAntiAlias(true)效果

1.1 p.setAlpha(0x80);\\透明度

1.2 p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));//14例中FingerPaint:手写板有这个用法

1.3 p.setTextSize(60);\\设置字体大小

1.4 p.setTextAlign(Paint.Align.CENTER);\\基准线

1.5 InputStream is = context.getResources().openRawResource(\\从drawable里的图片转到bitmap
R.drawable.app_sample_code);
mBitmap = BitmapFactory.decodeStream(is);

1.6 mShader = new LinearGradient(0, 0, 100, 70, new int[] { Color.RED,\\渐变
Color.GREEN, Color.BLUE }, null, Shader.TileMode.MIRROR);

p.setShader(mShader);

2.AnimateDrawables 把一张照片动起来，类似跑马灯的效果，有三个类AnimateDrawables ，AnimateDrawable，ProxyDrawable

2.1 Drawable dr = context.getResources().getDrawable(R.drawable.beach);\\获得Drawable
dr.setBounds(0, 0, dr.getIntrinsicWidth(), dr.getIntrinsicHeight());\\设置图的边界，有放大缩小的作用这是设置为100，100的边界效果

2.2 Animation an = new TranslateAnimation(0, 100, 0, 200);\\从0，0点到100，200移动的动画
an.setDuration(2000);\\持续时间2秒
an.setRepeatCount(-1);\\无限循环

2.3 public void draw(Canvas canvas) {
Drawable dr = getProxy();
if (dr != null) {
int sc = canvas.save();//
Animation anim = mAnimation;
if (anim != null) {
anim.getTransformation(AnimationUtils.currentAnimationTimeMillis()\\动起来
mTransformation);//该方法根据当前间 (currentTime) 和 interpolator，计算当前的变换，在 outTransformation 中返回
canvas.concat(mTransformation.getMatrix());\\对canvas应用矩阵变换
}
dr.draw(canvas);
canvas.restoreToCount(sc);
}
}

注意：canvas.save();//canvas.restoreToCount(sc);是正对出现的
假设我们将要对canvas进行了一系列的设置，例如旋转，变色等，而又不希望在操作完之后让这些设置影响到后面的绘画。
就需要在设置前先save，使用完之后再restore；带count的恢复，是指直接回复到某个状态

假设我们设置了clip去绘画一张图片的一小部分
一般这么干
canvas.save();
canvas.setclip
canvas.drawBitmap
canvas.restore();

3. Arcs：

3.1 mPaints[0] = new Paint();
mPaints[0].setAntiAlias(true);
mPaints[0].setStyle(Paint.Style.FILL);
mPaints[0].setColor(0x88FF0000);
mUseCenters[0] = false;

mPaints[1] = new Paint(mPaints[0]);
mPaints[1].setColor(0x8800FF00);
mUseCenters[1] = true;

mPaints[2] = new Paint(mPaints[0]);
mPaints[2].setStyle(Paint.Style.STROKE);
mPaints[2].setStrokeWidth(4);
mPaints[2].setColor(0x880000FF);
mUseCenters[2] = false;

3.2 canvas.drawArc(oval, mStart, mSweep, useCenter, paint); \\useCenter为是否画中心。mStart起始度数，mSweep跨度

4.BitmapDecode：最下面的国旗是GIF动画

4.1 两种加载图片，再转成bitmap的方法

// now opts.outWidth and opts.outHeight are the dimension of the
// bitmap, even though bm is null

opts.inJustDecodeBounds = false; // this will request the bm
opts.inSampleSize = 4; // scaled down by 4 面试变成1/4大小
bm = BitmapFactory.decodeStream(is, null, opts);

mBitmap = bm;

// decode an image with transparency
is = context.getResources().openRawResource(R.drawable.frog);
mBitmap2 = BitmapFactory.decodeStream(is);

4.2 mBitmap2.getPixels(pixels, 0, w, 0, 0, w, h);//获得mBitmap2的像素颜色值，赋值给pixels，第三个参数为一行的像素数（矩形的宽）

mBitmap3 = Bitmap.createBitmap(pixels, 0, w, w, h,
Bitmap.Config.ARGB_8888);//用上面的pixels颜色数组创建一个Bitmap

4.3 mDrawable = context.getResources().getDrawable(R.drawable.button);
mDrawable.setBounds(150, 20, 300, 100);//设置button9的面积（只有Drawable才有这个方法）

4.4 canvas.drawBitmap(mBitmap4, 210, 170, null); //Bitmap的画法

mDrawable.draw(canvas);//Drawable的画法

4.5 is = context.getResources().openRawResource(R.drawable.animated_gif);//获得GIF动画流

mMovie = Movie.decodeStream(is);//把流转成Movie

//画Movie动画

long now = android.os.SystemClock.uptimeMillis();//当前时间
if (mMovieStart == 0) { // first time
mMovieStart = now;
}
if (mMovie != null) {
int dur = mMovie.duration();//GIF持续时间
if (dur == 0) {
dur = 1000;
}
int relTime = (int) ((now - mMovieStart) % dur);
mMovie.setTime(relTime);
mMovie.draw(canvas, getWidth() - mMovie.width(), getHeight()//画动画，参数为X,Y点
- mMovie.height());
invalidate();//刷新，不停的画
}

5. BitmapMesh：(没看)

5.1 mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.beach); //生成Bitmap

6.BitmapPixels：（没看）

7. CameraPreview：（没看）内容同SDK开发大全中的7.15例

7.1 // Hide the window title.隐藏标题
requestWindowFeature(Window.FEATURE_NO_TITLE);

8. Clipping：

8.1

//定好样式

mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(6);//画笔的宽
mPaint.setTextSize(16);
mPaint.setTextAlign(Paint.Align.RIGHT);

canvas.drawLine(0, 0, 100, 100, mPaint);//画线画的线为mPaint指定的宽度

8.2

canvas.save();
canvas.translate(160, 10);
canvas.clipRect(10, 10, 90, 90);
canvas.clipRect(30, 30, 70, 70, Region.Op.DIFFERENCE);
drawScene(canvas);
canvas.restore();

8.3

canvas.save();
canvas.translate(10, 160);
mPath.reset();
canvas.clipPath(mPath); // makes the clip empty
mPath.addCircle(50, 50, 50, Path.Direction.CCW);
canvas.clipPath(mPath, Region.Op.REPLACE);
drawScene(canvas);
canvas.restore();

9. ColorFilters：

9.1

Paint.FontMetrics fm = mPaint.getFontMetrics();//不知道是什么意思？？？？？？
float mPaintTextOffset = (fm.descent + fm.ascent) * 0.5f;

9.2

mColors = new int[] { 0, 0xCC0000FF, 0x880000FF, 0x440000FF, 0xFFCCCCFF,
0xFF8888FF, 0xFF4444FF, };

mModes = new PorterDuff.Mode[] { PorterDuff.Mode.SRC_ATOP,//过滤器的方式
PorterDuff.Mode.MULTIPLY, };
mModeIndex = 0;

filter = new PorterDuffColorFilter(mColors [i], mModes[mModeIndex]);//用mColors [i]和porter-duff mode的颜色创建一个颜色过滤

mDrawable.setColorFilter(filter);
mDrawable.draw(canvas);

10.ColorMatrixTest

private void setContrast(ColorMatrix cm, float contrast) {
float scale = contrast + 1.f;
float translate = (-.5f * scale + .5f) * 255.f;
cm.set(new float[] { scale, 0, 0, 0, translate, 0, scale, 0, 0,
translate, 0, 0, scale, 0, translate, 0, 0, 0, 1, 0 });
}

ColorMatrix cm = new ColorMatrix();

mAngle += 2;
if (mAngle > 180) {
mAngle = 0;
}

float contrast = mAngle / 180.f;

setContrast(cm, contrast);
paint.setColorFilter(new ColorMatrixColorFilter(cm));//设置颜色过滤
canvas.drawBitmap(mBitmap, x + mBitmap.getWidth() + 10, y, paint);
invalidate();

11.Compass指南针：（没看）

12.CreateBitmap：

12.1 创建颜色数组（说实话没看懂）

private static int[] createColors() {
int[] colors = new int[STRIDE * HEIGHT];
for (int y = 0; y < HEIGHT; y++) {
for (int x = 0; x < WIDTH; x++) {
int r = x * 255 / (WIDTH - 1);
int g = y * 255 / (HEIGHT - 1);
int b = 255 - Math.min(r, g);
int a = Math.max(r, g);
colors[y * STRIDE + x] = (a << 24) | (r << 16) | (g << 8) | b;
}
}
return colors;
}

12.2

private static Bitmap codec(Bitmap src, Bitmap.CompressFormat format,
int quality) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
src.compress(format, quality, os); //压缩

byte[] array = os.toByteArray();
return BitmapFactory.decodeByteArray(array, 0, array.length);
}

mJPEG[i] = codec(mBitmaps[i], Bitmap.CompressFormat.JPEG, 80);//用JPEG编码

13.DensityActivity

13.1

 1:  LinearLayout root = new LinearLayout(this);//设置一个线性布局root

 2:          root.setOrientation(LinearLayout.VERTICAL); //方向垂直

3:

 4:          LinearLayout layout = new LinearLayout(this);//在root布局内，又建一个layout布局

 5:          addBitmapDrawable(layout, R.drawable.logo120dpi, true);//以logo120dpi为View的背景，并把view加下布局

6:

7:

 8:          addBitmapDrawable(layout, R.drawable.logo160dpi, true);

 9:          //addBitmapDrawable(layout, R.drawable.logo240dpi, true);

10:          addLabelToRoot(root, "Prescaled bitmap in drawable");//加入一个TextView到root

11:          addChildToRoot(root, layout);

12:          setContentView(scrollWrap(root));

13:

14:      }

15:

16:

 1:  private void addLabelToRoot(LinearLayout root, String text) {

 2:          TextView label = new TextView(this);

 3:          label.setText(text);

 4:          root.addView(label, new LinearLayout.LayoutParams(

 5:              LinearLayout.LayoutParams.FILL_PARENT,

 6:              LinearLayout.LayoutParams.WRAP_CONTENT));

 7:      }

8:

 9:      private void addChildToRoot(LinearLayout root, LinearLayout layout) {

10:          root.addView(layout, new LinearLayout.LayoutParams(

11:              LinearLayout.LayoutParams.FILL_PARENT,

12:              LinearLayout.LayoutParams.WRAP_CONTENT));

13:      }

14:

15:

16:      private Bitmap loadAndPrintDpi(int id, boolean scale) {

17:          Bitmap bitmap;

18:          if (scale) {

19:              bitmap = BitmapFactory.decodeResource(getResources(), id);

20:          } else {

21:              BitmapFactory.Options opts = new BitmapFactory.Options();

22:              opts.inScaled = false;

23:              bitmap = BitmapFactory.decodeResource(getResources(), id, opts);

24:          }

25:          return bitmap;

26:      }

27:

28:

//将bitmap为作View的背景，并把view加下布局

 1:  private void addBitmapDrawable(LinearLayout layout, int resource,

 2:          boolean scale) {

 3:          Bitmap bitmap;

 4:          bitmap = loadAndPrintDpi(resource, scale);

5:

 6:          final View view = new View(this);

 7:          view.setOnClickListener(new View.OnClickListener() {//给当前veiw设置OnOnClickListener

 8:              @Override

 9:              public void onClick(View v) {

10:                  //Toast.makeText(NewViewTest.this,"View onClick" , Toast.LENGTH_LONG).show();

11:              }

12:          });

13:          view.setOnTouchListener(new View.OnTouchListener() {//给当前view设置OnTouchListener

14:              @Override

15:              public boolean onTouch(View v, MotionEvent event) {

16:                  Toast.makeText(NewViewTest.this,"x="+event.getX()+" y="+event.getY() , Toast.LENGTH_LONG).show();

17:                  v.setBackgroundColor(Color.BLUE);

18:

19:                  return false;

20:              }

21:          });

22:          final BitmapDrawable d = new BitmapDrawable(getResources(), bitmap);

23:          if (!scale)

24:              d.setTargetDensity(getResources().getDisplayMetrics());

25:          view.setBackgroundDrawable(d);

26:

27:          view.setLayoutParams(new LinearLayout.LayoutParams(d.getIntrinsicWidth(), d

28:              .getIntrinsicHeight()));

29:          layout.addView(view);

30:      }

31:      private View scrollWrap(View view) {

32:          ScrollView scroller = new ScrollView(this);

33:          scroller.addView(view, new ScrollView.LayoutParams(

34:              ScrollView.LayoutParams.FILL_PARENT,

35:              ScrollView.LayoutParams.FILL_PARENT));

36:          return scroller;

37:      }

38:

39:

14. FingerPaint:手写板

14.1

1:  MaskFilter mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f); //浮雕

2:

3:      MaskFilter    mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);//模糊

4:

14.2

//触摸事件

 1:  public boolean onTouchEvent(MotionEvent event) {

 2:              float x = event.getX();

 3:              float y = event.getY();

4:

 5:              switch (event.getAction()) {

 6:              case MotionEvent.ACTION_DOWN:

 7:                  touch_start(x, y);

 8:                  invalidate();

 9:                  break;

10:              case MotionEvent.ACTION_MOVE:

11:                  touch_move(x, y);

12:                  invalidate();

13:                  break;

14:              case MotionEvent.ACTION_UP:

15:                  touch_up();

16:                  invalidate();

17:                  break;

18:              }

19:              return true;

20:          }

21:

14.3 画路径

 1:  private float mX, mY;

 2:          private static final float TOUCH_TOLERANCE = 4;

3:

 4:          private void touch_start(float x, float y) {

 5:              mPath.reset();

 6:              mPath.moveTo(x, y);//设置起始点

 7:              mX = x;

 8:              mY = y;

 9:          }

10:

11:          private void touch_move(float x, float y) {

12:              float dx = Math.abs(x - mX);

13:              float dy = Math.abs(y - mY);

14:              if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {

15:                  mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);

16:                  mX = x;

17:                  mY = y;

18:              }

19:          }

20:

21:          private void touch_up() {

22:              mPath.lineTo(mX, mY);

padding-bottom: 0px !important; line-height: 18px; background-color: #f7f7ff !important; margin: 0em; padding-lef

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2010-05-15 23:44
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