BasePageIndicator-ViewPager指示器

BasePageIndicator-ViewPager指示器

参考JakeWharton/ViewPagerIndicator和astuetz/PagerSlidingTabStrip的源码，感谢。

初衷是想自定义个指示器，看了上述的源码，干脆自己写出来了一个通用的BasePageIndicator，自定义指示器只需重写以下方法：

getTabItemView()

drawItemUnder()

drawTabUnder()

drawDivider()

，第一个方法是得到item的view，后面几个是绘制Item下划线，Tab下划线，Item间的分隔线。

贴上几个常用的。

TitleIndicator

代码：

/**
* Created by blanke on 15-12-6.
*/
public class TitleIndicator extends BaseIndicator {
private int mTextSize = 16;
private int mTextColorResId;

public TitleIndicator(Context context) {
this(context, null);
}

public TitleIndicator(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
protected View getTabItemView(PagerAdapter adapter, int position) {
TextView view = new TextView(getContext());
view.setText(adapter.getPageTitle(position));
view.setTextSize(mTextSize);
view.setGravity(Gravity.CENTER);
if (mTextColorResId != 0) {
view.setTextColor(getResources().getColorStateList(mTextColorResId));
}
return view;
}

@Override
protected void drawItemUnder(Canvas canvas, float left, float top, float right, float bottom, Paint paint) {
if (paint != null) {
canvas.drawRect(left, top, right, bottom, paint);
}
}

@Override
protected void drawTabUnder(Canvas canvas, float left, float top, float right, float bottom, Paint paint) {
canvas.drawRect(left, top, right, bottom, paint);
}

@Override
protected void drawDivider(Canvas canvas, float left, float top, float right, float bottom, Paint paint) {
canvas.drawRect(left, top, right, bottom, paint);
}

/*.... get() set()*/
}

MIUITitleIndicator

代码;

/**
* Created by blanke on 15-12-6.
*/
public class MIUITitleIndicator extends TitleIndicator {
private Path mPath;
private float mSplitFactory = 4;//控制三角形的大小
private float mVerticalOffset = 5;//纵向偏移
private float r;//三角形底边长

public MIUITitleIndicator(Context context) {
this(context, null);
}

public MIUITitleIndicator(Context context, AttributeSet attrs) {
super(context, attrs);
getItemUnderPaint().setPathEffect(new CornerPathEffect(3));
}

@Override
protected View getTabItemView(PagerAdapter adapter, int position) {
final View v = super.getTabItemView(adapter, position);
if (position == 0 && mPath == null) {
v.post(new Runnable() {
@Override
public void run() {
if (mPath == null) {
initPath(v.getWidth());
}
}
});
}
return v;
}

private void initPath(float viewWidth) {
r = viewWidth / mSplitFactory;
mPath = new Path();
mPath.moveTo(0, 0);
mPath.lineTo(r, 0);
mPath.lineTo(r / 2, -r / 2);
mPath.close();
invalidate();//重绘
}

@Override
protected void drawItemUnder(Canvas canvas, float left, float top, float right, float bottom, Paint paint) {
if (mPath != null) {
canvas.save();
canvas.translate((left + right - r) / 2, bottom + mVerticalOffset);
canvas.drawPath(mPath, paint);
canvas.restore();
}
}
/*...get() set()*/
}

写的不完善，仅供参考。

github:https://github.com/Blankeer/BasePageIndicator