今天改需求改的我头疼，最可气的是，测试悠哉游哉的跑过来，丢下一句"哟，又写BUG呢？"，我一想我也不是惯孩子人啊？当时我就回了一句，"正写着呢？要不晚上一起加班啊？请你吃好吃的"，这货居然说"行啊！"吃货的世界真的不懂！但是真心说一句，改需求能不能不这么从容，每次都是马上上线了，淡定的丢下一句，不行改改吧！我的心里是这样的。。。
image
本来都准备好下班打卡出去浪的。只能坐在那里改、改、改。总说我们程序员是单身汪，能不单身吗？然后每次改好了需求等测试反馈还是这样的！！！
image
好吧！！！原谅我的放纵，被公司看见会不会被打死？？？我要去看我的秘籍了。。。
一位具有多年开发经验的人推荐
好了不扯淡了!
本文知识点
- CardView是什么？
- CardView有哪些属性可以设置？
- CardView的简单使用？
- CardView的适配问题？
1.CardView是什么？
CardView是google在5.0中提供带圆角和阴影的布局，继承自FrameLayout。
2.CardView的一些属性设置
- android:cardBackgroundColor 设置背景
- android:cardCornerRadius 设置圆角
- app:cardElevation 设置阴影大小
- app:cardMaxElevation 设置阴影的最大高度
- app:contentPadding 内容距离边界的距离
- app:contentPaddingXXX 设置局部的内边距，替换Padding的，在CardView中设置Padding是不起作用的。
- app:cardUseCompatPadding 如果您需要将CardView与其他视图对齐，可能在21以下，可以将此标志设置为true，CardView将在21之后的平台上添加相同的填充值。
- app:cardPreventCornerOverlap 是否裁剪边界以防止重叠
能设置的属性就这么多了，没有什么好说的。但是最后两个属性会在后面的时候详细讲解，涉及到相应的适配！
3. CardView的简单使用
其实在平时的开发中，如果不考虑适配的话，CardView使用起来是很简单，但是说起适配的话，感觉真心头疼。我第一次用CardView的时候，弄适配弄了两个多消失，当时觉得天都是黑的！！！先看简单的效果吧。。。
<android.support.v7.widget.CardView
android:id="@+id/cv1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
app:cardBackgroundColor="#c4c6c8"
app:cardCornerRadius="10dp"
app:cardElevation="10dp"
app:cardPreventCornerOverlap="true"
app:layout_constraintTop_toTopOf="parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@mipmap/heard_1" />
</android.support.v7.widget.CardView>
效果是这个样子的。。。
效果还是可以的
注意啊这个是5.0以上的手机拍的，它默认帮我们把圆角裁剪了(如果你设置了圆角的话)。按照上面的属性进行设置就可以了！
4.CardView的适配问题
这个才是本片文章的重点问题！如果没有做过适配的人，会觉得CardView很简单的。但是如果让你适配的话，你就。。。先来看一张照片！
image
重点的地方，我都标记出来了，如果你们产品和美工能容忍的话。那只能说你跟他们有一腿！
4.1 关于内边距的问题！
图片上下左右的边距比较好处理，因为上面提到了两个属性
app:cardUseCompatPadding="true"
app:cardPreventCornerOverlap="false"
- 属性1： 这个属性如果你设置成true的话，那么就能保证所有版本的Padding都设置相同的Padding，默认是false，就像上面这张图一样，会留出一定的边距！
- 属性2： 是否裁剪边角，以保证边角是圆形的！在21以上的版本，默认是帮你裁剪好圆角的，但是21之前的版本是不会帮你裁剪的，会出现下面这种！
image
内边距是不见了，但是圆角的处理就成了接下来的问题了。
4.2 关于圆角的处理
最开始我以为设置上面两个属性就能轻松的设置圆角了呢？太相信谷歌了。然后我的想法就是找一个处理圆角的控件，但是找了好久，基本上都是处理四个圆角的，没有单个圆角的处理，当时产品的意思是只处理左边的两个圆角。好吧，继续找，最后中于找到了。当时给大家发个福利了！哈哈，我真的不知道怎么上传相应的文件。原谅我的无知！
public class SelectableRoundedImageView extends ImageView {
public static final String TAG = "SelectableRoundedImageView";
private int mResource = 0;
private static final ScaleType[] sScaleTypeArray = {
ScaleType.MATRIX,
ScaleType.FIT_XY,
ScaleType.FIT_START,
ScaleType.FIT_CENTER,
ScaleType.FIT_END,
ScaleType.CENTER,
ScaleType.CENTER_CROP,
ScaleType.CENTER_INSIDE
};
// Set default scale type to FIT_CENTER, which is default scale type of
// original ImageView.
private ScaleType mScaleType = ScaleType.FIT_CENTER;
private float mLeftTopCornerRadius = 0.0f;
private float mRightTopCornerRadius = 0.0f;
private float mLeftBottomCornerRadius = 0.0f;
private float mRightBottomCornerRadius = 0.0f;
private float mBorderWidth = 0.0f;
private static final int DEFAULT_BORDER_COLOR = Color.BLACK;
private ColorStateList mBorderColor = ColorStateList.valueOf(DEFAULT_BORDER_COLOR);
private boolean isOval = false;
private Drawable mDrawable;
private float[] mRadii = new float[] { 0, 0, 0, 0, 0, 0, 0, 0 };
public SelectableRoundedImageView(Context context) {
super(context);
}
public SelectableRoundedImageView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public SelectableRoundedImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.SelectableRoundedImageView, defStyle, 0);
final int index = a.getInt(R.styleable.SelectableRoundedImageView_android_scaleType, -1);
if (index >= 0) {
setScaleType(sScaleTypeArray[index]);
}
mLeftTopCornerRadius = a.getDimensionPixelSize(
R.styleable.SelectableRoundedImageView_sriv_left_top_corner_radius, 0);
mRightTopCornerRadius = a.getDimensionPixelSize(
R.styleable.SelectableRoundedImageView_sriv_right_top_corner_radius, 0);
mLeftBottomCornerRadius = a.getDimensionPixelSize(
R.styleable.SelectableRoundedImageView_sriv_left_bottom_corner_radius, 0);
mRightBottomCornerRadius = a.getDimensionPixelSize(
R.styleable.SelectableRoundedImageView_sriv_right_bottom_corner_radius, 0);
if (mLeftTopCornerRadius < 0.0f || mRightTopCornerRadius < 0.0f
|| mLeftBottomCornerRadius < 0.0f || mRightBottomCornerRadius < 0.0f) {
throw new IllegalArgumentException("radius values cannot be negative.");
}
mRadii = new float[] {
mLeftTopCornerRadius, mLeftTopCornerRadius,
mRightTopCornerRadius, mRightTopCornerRadius,
mRightBottomCornerRadius, mRightBottomCornerRadius,
mLeftBottomCornerRadius, mLeftBottomCornerRadius };
mBorderWidth = a.getDimensionPixelSize(
R.styleable.SelectableRoundedImageView_sriv_border_width, 0);
if (mBorderWidth < 0) {
throw new IllegalArgumentException("border width cannot be negative.");
}
mBorderColor = a
.getColorStateList(R.styleable.SelectableRoundedImageView_sriv_border_color);
if (mBorderColor == null) {
mBorderColor = ColorStateList.valueOf(DEFAULT_BORDER_COLOR);
}
isOval = a.getBoolean(R.styleable.SelectableRoundedImageView_sriv_oval, false);
a.recycle();
updateDrawable();
}
@Override
protected void drawableStateChanged() {
super.drawableStateChanged();
invalidate();
}
@Override
public ScaleType getScaleType() {
return mScaleType;
}
@Override
public void setScaleType(ScaleType scaleType) {
super.setScaleType(scaleType);
mScaleType = scaleType;
updateDrawable();
}
@Override
public void setImageDrawable(Drawable drawable) {
mResource = 0;
mDrawable = SelectableRoundedCornerDrawable.fromDrawable(drawable, getResources());
super.setImageDrawable(mDrawable);
updateDrawable();
}
@Override
public void setImageBitmap(Bitmap bm) {
mResource = 0;
mDrawable = SelectableRoundedCornerDrawable.fromBitmap(bm, getResources());
super.setImageDrawable(mDrawable);
updateDrawable();
}
@Override
public void setImageResource(int resId) {
if (mResource != resId) {
mResource = resId;
mDrawable = resolveResource();
super.setImageDrawable(mDrawable);
updateDrawable();
}
}
@Override
public void setImageURI(Uri uri) {
super.setImageURI(uri);
setImageDrawable(getDrawable());
}
private Drawable resolveResource() {
Resources rsrc = getResources();
if (rsrc == null) {
return null;
}
Drawable d = null;
if (mResource != 0) {
try {
d = rsrc.getDrawable(mResource);
} catch (NotFoundException e) {
// Don't try again.
mResource = 0;
}
}
return SelectableRoundedCornerDrawable.fromDrawable(d, getResources());
}
private void updateDrawable() {
if (mDrawable == null) {
return;
}
((SelectableRoundedCornerDrawable) mDrawable).setScaleType(mScaleType);
((SelectableRoundedCornerDrawable) mDrawable).setCornerRadii(mRadii);
((SelectableRoundedCornerDrawable) mDrawable).setBorderWidth(mBorderWidth);
((SelectableRoundedCornerDrawable) mDrawable).setBorderColor(mBorderColor);
((SelectableRoundedCornerDrawable) mDrawable).setOval(isOval);
}
public float getCornerRadius() {
return mLeftTopCornerRadius;
}
/**
* Set radii for each corner.
*
* @param leftTop The desired radius for left-top corner in dip.
* @param rightTop The desired desired radius for right-top corner in dip.
* @param leftBottom The desired radius for left-bottom corner in dip.
* @param rightBottom The desired radius for right-bottom corner in dip.
*
*/
public void setCornerRadiiDP(float leftTop, float rightTop, float leftBottom, float rightBottom) {
final float density = getResources().getDisplayMetrics().density;
final float lt = leftTop * density;
final float rt = rightTop * density;
final float lb = leftBottom * density;
final float rb = rightBottom * density;
mRadii = new float[] { lt, lt, rt, rt, rb, rb, lb, lb };
updateDrawable();
}
public float getBorderWidth() {
return mBorderWidth;
}
/**
* Set border width.
*
* @param width
* The desired width in dip.
*/
public void setBorderWidthDP(float width) {
float scaledWidth = getResources().getDisplayMetrics().density * width;
if (mBorderWidth == scaledWidth) {
return;
}
mBorderWidth = scaledWidth;
updateDrawable();
invalidate();
}
public int getBorderColor() {
return mBorderColor.getDefaultColor();
}
public void setBorderColor(int color) {
setBorderColor(ColorStateList.valueOf(color));
}
public ColorStateList getBorderColors() {
return mBorderColor;
}
public void setBorderColor(ColorStateList colors) {
if (mBorderColor.equals(colors)) {
return;
}
mBorderColor = (colors != null) ? colors : ColorStateList
.valueOf(DEFAULT_BORDER_COLOR);
updateDrawable();
if (mBorderWidth > 0) {
invalidate();
}
}
public boolean isOval() {
return isOval;
}
public void setOval(boolean oval) {
isOval = oval;
updateDrawable();
invalidate();
}
static class SelectableRoundedCornerDrawable extends Drawable {
private static final String TAG = "SelectableRoundedCornerDrawable";
private static final int DEFAULT_BORDER_COLOR = Color.BLACK;
private RectF mBounds = new RectF();
private RectF mBorderBounds = new RectF();
private final RectF mBitmapRect = new RectF();
private final int mBitmapWidth;
private final int mBitmapHeight;
private final Paint mBitmapPaint;
private final Paint mBorderPaint;
private BitmapShader mBitmapShader;
private float[] mRadii = new float[] { 0, 0, 0, 0, 0, 0, 0, 0 };
private float[] mBorderRadii = new float[] { 0, 0, 0, 0, 0, 0, 0, 0 };
private boolean mOval = false;
private float mBorderWidth = 0;
private ColorStateList mBorderColor = ColorStateList.valueOf(DEFAULT_BORDER_COLOR);
// Set default scale type to FIT_CENTER, which is default scale type of
// original ImageView.
private ScaleType mScaleType = ScaleType.FIT_CENTER;
private Path mPath = new Path();
private Bitmap mBitmap;
private boolean mBoundsConfigured = false;
public SelectableRoundedCornerDrawable(Bitmap bitmap, Resources r) {
mBitmap = bitmap;
mBitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
if (bitmap != null) {
mBitmapWidth = bitmap.getScaledWidth(r.getDisplayMetrics());
mBitmapHeight = bitmap.getScaledHeight(r.getDisplayMetrics());
} else {
mBitmapWidth = mBitmapHeight = -1;
}
mBitmapRect.set(0, 0, mBitmapWidth, mBitmapHeight);
mBitmapPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mBitmapPaint.setStyle(Paint.Style.FILL);
mBitmapPaint.setShader(mBitmapShader);
mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mBorderPaint.setStyle(Paint.Style.STROKE);
mBorderPaint.setColor(mBorderColor.getColorForState(getState(), DEFAULT_BORDER_COLOR));
mBorderPaint.setStrokeWidth(mBorderWidth);
}
public static SelectableRoundedCornerDrawable fromBitmap(Bitmap bitmap, Resources r) {
if (bitmap != null) {
return new SelectableRoundedCornerDrawable(bitmap, r);
} else {
return null;
}
}
public static Drawable fromDrawable(Drawable drawable, Resources r) {
if (drawable != null) {
if (drawable instanceof SelectableRoundedCornerDrawable) {
return drawable;
} else if (drawable instanceof LayerDrawable) {
LayerDrawable ld = (LayerDrawable) drawable;
final int num = ld.getNumberOfLayers();
for (int i = 0; i < num; i++) {
Drawable d = ld.getDrawable(i);
ld.setDrawableByLayerId(ld.getId(i), fromDrawable(d, r));
}
return ld;
}
Bitmap bm = drawableToBitmap(drawable);
if (bm != null) {
return new SelectableRoundedCornerDrawable(bm, r);
} else {
}
}
return drawable;
}
public static Bitmap drawableToBitmap(Drawable drawable) {
if (drawable == null) {
return null;
}
if (drawable instanceof BitmapDrawable) {
return ((BitmapDrawable) drawable).getBitmap();
}
Bitmap bitmap;
int width = Math.max(drawable.getIntrinsicWidth(), 2);
int height = Math.max(drawable.getIntrinsicHeight(), 2);
try {
bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
} catch (IllegalArgumentException e) {
e.printStackTrace();
bitmap = null;
}
return bitmap;
}
@Override
public boolean isStateful() {
return mBorderColor.isStateful();
}
@Override
protected boolean onStateChange(int[] state) {
int newColor = mBorderColor.getColorForState(state, 0);
if (mBorderPaint.getColor() != newColor) {
mBorderPaint.setColor(newColor);
return true;
} else {
return super.onStateChange(state);
}
}
private void configureBounds(Canvas canvas) {
// I have discovered a truly marvelous explanation of this,
// which this comment space is too narrow to contain. :)
// If you want to understand what's going on here,
// See http://www.joooooooooonhokim.com/?p=289
Rect clipBounds = canvas.getClipBounds();
Matrix canvasMatrix = canvas.getMatrix();
if (ScaleType.CENTER == mScaleType) {
mBounds.set(clipBounds);
} else if (ScaleType.CENTER_CROP == mScaleType) {
applyScaleToRadii(canvasMatrix);
mBounds.set(clipBounds);
} else if (ScaleType.FIT_XY == mScaleType) {
Matrix m = new Matrix();
m.setRectToRect(mBitmapRect, new RectF(clipBounds), Matrix.ScaleToFit.FILL);
mBitmapShader.setLocalMatrix(m);
mBounds.set(clipBounds);
} else if (ScaleType.FIT_START == mScaleType || ScaleType.FIT_END == mScaleType
|| ScaleType.FIT_CENTER == mScaleType || ScaleType.CENTER_INSIDE == mScaleType) {
applyScaleToRadii(canvasMatrix);
mBounds.set(mBitmapRect);
} else if (ScaleType.MATRIX == mScaleType) {
applyScaleToRadii(canvasMatrix);
mBounds.set(mBitmapRect);
}
}
private void applyScaleToRadii(Matrix m) {
float[] values = new float[9];
m.getValues(values);
for (int i = 0; i < mRadii.length; i++) {
mRadii[i] = mRadii[i] / values[0];
}
}
private void adjustCanvasForBorder(Canvas canvas) {
Matrix canvasMatrix = canvas.getMatrix();
final float[] values = new float[9];
canvasMatrix.getValues(values);
final float scaleFactorX = values[0];
final float scaleFactorY = values[4];
final float translateX = values[2];
final float translateY = values[5];
final float newScaleX = mBounds.width()
/ (mBounds.width() + mBorderWidth + mBorderWidth);
final float newScaleY = mBounds.height()
/ (mBounds.height() + mBorderWidth + mBorderWidth);
canvas.scale(newScaleX, newScaleY);
if (ScaleType.FIT_START == mScaleType || ScaleType.FIT_END == mScaleType
|| ScaleType.FIT_XY == mScaleType || ScaleType.FIT_CENTER == mScaleType
|| ScaleType.CENTER_INSIDE == mScaleType || ScaleType.MATRIX == mScaleType) {
canvas.translate(mBorderWidth, mBorderWidth);
} else if (ScaleType.CENTER == mScaleType || ScaleType.CENTER_CROP == mScaleType) {
// First, make translate values to 0
canvas.translate(
-translateX / (newScaleX * scaleFactorX),
-translateY / (newScaleY * scaleFactorY));
// Then, set the final translate values.
canvas.translate(-(mBounds.left - mBorderWidth), -(mBounds.top - mBorderWidth));
}
}
private void adjustBorderWidthAndBorderBounds(Canvas canvas) {
Matrix canvasMatrix = canvas.getMatrix();
final float[] values = new float[9];
canvasMatrix.getValues(values);
final float scaleFactor = values[0];
float viewWidth = mBounds.width() * scaleFactor;
mBorderWidth = (mBorderWidth * mBounds.width()) / (viewWidth - (2 * mBorderWidth));
mBorderPaint.setStrokeWidth(mBorderWidth);
mBorderBounds.set(mBounds);
mBorderBounds.inset(- mBorderWidth / 2, - mBorderWidth / 2);
}
private void setBorderRadii() {
for (int i = 0; i < mRadii.length; i++) {
if (mRadii[i] > 0) {
mBorderRadii[i] = mRadii[i];
mRadii[i] = mRadii[i] - mBorderWidth;
}
}
}
@Override
public void draw(Canvas canvas) {
canvas.save();
if (!mBoundsConfigured) {
configureBounds(canvas);
if (mBorderWidth > 0) {
adjustBorderWidthAndBorderBounds(canvas);
setBorderRadii();
}
mBoundsConfigured = true;
}
if (mOval) {
if (mBorderWidth > 0) {
adjustCanvasForBorder(canvas);
mPath.addOval(mBounds, Path.Direction.CW);
canvas.drawPath(mPath, mBitmapPaint);
mPath.reset();
mPath.addOval(mBorderBounds, Path.Direction.CW);
canvas.drawPath(mPath, mBorderPaint);
} else {
mPath.addOval(mBounds, Path.Direction.CW);
canvas.drawPath(mPath, mBitmapPaint);
}
} else {
if (mBorderWidth > 0) {
adjustCanvasForBorder(canvas);
mPath.addRoundRect(mBounds, mRadii, Path.Direction.CW);
canvas.drawPath(mPath, mBitmapPaint);
mPath.reset();
mPath.addRoundRect(mBorderBounds, mBorderRadii, Path.Direction.CW);
canvas.drawPath(mPath, mBorderPaint);
} else {
mPath.addRoundRect(mBounds, mRadii, Path.Direction.CW);
canvas.drawPath(mPath, mBitmapPaint);
}
}
canvas.restore();
}
public void setCornerRadii(float[] radii) {
if (radii == null)
return;
if (radii.length != 8) {
throw new ArrayIndexOutOfBoundsException("radii[] needs 8 values");
}
for (int i = 0; i < radii.length; i++) {
mRadii[i] = radii[i];
}
}
@Override
public int getOpacity() {
return (mBitmap == null || mBitmap.hasAlpha() || mBitmapPaint.getAlpha() < 255) ? PixelFormat.TRANSLUCENT
: PixelFormat.OPAQUE;
}
@Override
public void setAlpha(int alpha) {
mBitmapPaint.setAlpha(alpha);
invalidateSelf();
}
@Override
public void setColorFilter(ColorFilter cf) {
mBitmapPaint.setColorFilter(cf);
invalidateSelf();
}
@Override
public void setDither(boolean dither) {
mBitmapPaint.setDither(dither);
invalidateSelf();
}
@Override
public void setFilterBitmap(boolean filter) {
mBitmapPaint.setFilterBitmap(filter);
invalidateSelf();
}
@Override
public int getIntrinsicWidth() {
return mBitmapWidth;
}
@Override
public int getIntrinsicHeight() {
return mBitmapHeight;
}
public float getBorderWidth() {
return mBorderWidth;
}
public void setBorderWidth(float width) {
mBorderWidth = width;
mBorderPaint.setStrokeWidth(width);
}
public int getBorderColor() {
return mBorderColor.getDefaultColor();
}
public void setBorderColor(int color) {
setBorderColor(ColorStateList.valueOf(color));
}
public ColorStateList getBorderColors() {
return mBorderColor;
}
/**
* Controls border color of this ImageView.
*
* @param colors
* The desired border color. If it's null, no border will be
* drawn.
*
*/
public void setBorderColor(ColorStateList colors) {
if (colors == null) {
mBorderWidth = 0;
mBorderColor = ColorStateList.valueOf(Color.TRANSPARENT);
mBorderPaint.setColor(Color.TRANSPARENT);
} else {
mBorderColor = colors;
mBorderPaint.setColor(mBorderColor.getColorForState(getState(),
DEFAULT_BORDER_COLOR));
}
}
public boolean isOval() {
return mOval;
}
public void setOval(boolean oval) {
mOval = oval;
}
public ScaleType getScaleType() {
return mScaleType;
}
public void setScaleType(ScaleType scaleType) {
if (scaleType == null) {
return;
}
mScaleType = scaleType;
}
}
}
自定义属性
<declare-styleable name="SelectableRoundedImageView">
<attr name="sriv_left_top_corner_radius" format="dimension"/>
<attr name="sriv_right_top_corner_radius" format="dimension"/>
<attr name="sriv_left_bottom_corner_radius" format="dimension"/>
<attr name="sriv_right_bottom_corner_radius" format="dimension"/>
<attr name="sriv_border_width" format="dimension"/>
<attr name="sriv_border_color" format="color"/>
<attr name="sriv_oval" format="boolean"/>
<attr name="android:scaleType"/>
</declare-styleable>
也忘记是哪位大神些的了，在这里谢谢作者的开源精神！使用的时候直接设置相应的边角就可以了！还是很方便的。。。今天就到这里吧，我可把我压箱底的东西都拿出来了，希望对你有帮助！好了，今天就到这里了，See You!!!
