自定义ViewPagerIndicator
ViewPagerIndicator是一个开源的类，非常灵活。比如可以实现如下结果：
自己试着自定义了一下，实现类似的结果！
package com.wang.demo_viewpagerindictor.view;
import java.util.List;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.CornerPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.TextView;
import com.wang.demo_viewpagerindictor.R;
public class ViewPagerIndicator extends LinearLayout {
/**
* 绘制三角形的画笔
*/
private Paint mPaint;
/**
* 构建三角形的Path
*/
private Path mPath;
/**
* 三角形的宽度
*/
private int mTriangleWidth;
/**
* 三角形的高度
*/
private int mTriangleHeight;
/**
* 三角高度规定为单个tag的1/6
*/
private static final float RADIO_TRIANGLE = 1.0F / 6;
/**
* 三角形的最大宽度
*/
private final int DIMENSION_TRIANGLE_WIDTH = (int) (getScreenWidth() / 3 * RADIO_TRIANGLE);
/**
* 初始时三角形的偏移量
*/
private int mInitTranslationX;
/**
* 手指滑动时的偏移量
*/
private int mTranslationX;
/**
* 默认tab的数量
*/
private static final int COUNT_DEFAULT_TAB = 4;
/**
* tab的实际数量
*/
private int mTabVisiableCount = COUNT_DEFAULT_TAB;
/**
* tab上的内容
*/
private List mTabTitles;
/**
* 与之捆绑的ViewPager
*/
private ViewPager mViewPager;
/**
* 标题正常时的颜色
*/
private static final int COLOR_TEXT_NORMAL = 0x77ffffff;
/**
* 标题选中时的颜色
*/
private static final int COLOR_TEXT_SELECTED = 0xffffffff;
public ViewPagerIndicator(Context context) {
this(context, null, 0);
}
public ViewPagerIndicator(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public ViewPagerIndicator(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray typedArray = context.obtainStyledAttributes(attrs,
R.styleable.ViewPagerIndicator);
mTabVisiableCount = typedArray.getInteger(R.styleable.ViewPagerIndicator_tab_count,
COUNT_DEFAULT_TAB);
if (mTabVisiableCount < 0) {
mTabVisiableCount = COUNT_DEFAULT_TAB;
}
typedArray.recycle();
// 初始化画笔
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(COLOR_TEXT_SELECTED);
mPaint.setStyle(Paint.Style.FILL);
// 设置线的效果，此为焦点圆角（r为3）
mPaint.setPathEffect(new CornerPathEffect(3));
// mPath=new Path();
}
/**
* 绘制三角
*/
@Override
protected void dispatchDraw(Canvas canvas) {
canvas.save();
// 平移到正确的位置
canvas.translate(mInitTranslationX + mTranslationX, getHeight() + 1);
canvas.drawPath(mPath, mPaint);
canvas.restore();
super.dispatchDraw(canvas);
}
/**
* ViewGroup的子类通常再次方法中调整布局
*/
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// 获得三角形的宽度
mTriangleWidth = (int) (w * 1.0f / mTabVisiableCount * RADIO_TRIANGLE);
// 控制三角形的宽度，不超过最大宽度
mTriangleWidth = Math.min(DIMENSION_TRIANGLE_WIDTH, mTriangleWidth);
// 初始化三角形
initTriangle();
// 初始时的偏移量
mInitTranslationX = getWidth() / mTabVisiableCount / 2 - mTriangleWidth / 2;
//下面三个值是相同的；不过我觉得用getScreenWidth比较合理
// Log.i("wangsongbin", "w:" + w + " getWidth():" + getWidth() + " screenWidth:"
// + getScreenWidth());
}
/**
* 初始化三角形
*/
private void initTriangle() {
mPath = new Path();
mTriangleHeight = (int) (mTriangleWidth / 2 * Math.sqrt(2));
mPath.moveTo(0, 0);
mPath.lineTo(mTriangleWidth, 0);
mPath.lineTo(mTriangleWidth / 2, -mTriangleHeight);
mPath.close();
}
/**
* 设置可见的tab数
*/
public void setVisiableTabCount(int count) {
this.mTabVisiableCount = count;
}
/**
* 设置标题内容（可选，可以在布局中写死）
*/
public void setTabItemTitles(List data) {
if (data != null && data.size() > 0) {
// 先移除所有子控件
this.removeAllViews();
this.mTabTitles = data;
for (String title : mTabTitles) {
// 添加view
this.addView(generateTextView(title));
}
// 设置item的点击事件
setItemClickListener();
}
}
/**
* 为LinearLayout的所有子控件设置点击事件
*/
private void setItemClickListener() {
int count = this.getChildCount();
for (int i = 0; i < count; i++) {
final int j = i;
View view = getChildAt(i);
view.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mViewPager.setCurrentItem(j);
}
});
}
}
/**
* 根据标题生成我们的TextView
*
* @param title
* @return
*/
private TextView generateTextView(String title) {
TextView tv = new TextView(getContext());
LinearLayout.LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
lp.width = getScreenWidth() / mTabVisiableCount;
tv.setGravity(Gravity.CENTER);
tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);
tv.setTextColor(COLOR_TEXT_NORMAL);
tv.setText(title);
tv.setLayoutParams(lp);
return tv;
}
/**
* 获得屏幕的宽度
*
* @return
*/
private int getScreenWidth() {
WindowManager mWindowManager = (WindowManager) getContext().getSystemService(
Context.WINDOW_SERVICE);
DisplayMetrics metrics = new DisplayMetrics();
mWindowManager.getDefaultDisplay().getMetrics(metrics);
return metrics.widthPixels;
}
/**
* 对外公布PageChangeListener的接口
*/
public interface PageChangeListener {
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels);
public void onPageSelected(int position);
public void onPageScrollStateChanged(int state);
}
private PageChangeListener mPageChangeListener;
/**
* 设施监听
*
* @param mPageChangeListener
*/
public void setOnPageChangeListener(PageChangeListener mPageChangeListener) {
this.mPageChangeListener = mPageChangeListener;
}
/**
* 设置相关联的ViewPager
*/
public void setViewPager(ViewPager mViewPager, int pos) {
this.mViewPager = mViewPager;
this.mViewPager.setOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
resetTextViewColor();
LightTextView(position);
if (mPageChangeListener != null) {
mPageChangeListener.onPageSelected(position);
}
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
scroll(position, positionOffset);
if (mPageChangeListener != null) {
mPageChangeListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
}
@Override
public void onPageScrollStateChanged(int state) {
if (mPageChangeListener != null) {
mPageChangeListener.onPageScrollStateChanged(state);
}
}
});
this.mViewPager.setCurrentItem(pos);
// 把修改文本颜色
LightTextView(pos);
}
/**
* 把选中标题的字体调亮一点
*/
private void LightTextView(int pos) {
View view = this.getChildAt(pos);
if (view instanceof TextView) {
((TextView) view).setTextColor(COLOR_TEXT_SELECTED);
}
}
/**
* 重置文本颜色
*/
private void resetTextViewColor() {
int count = getChildCount();
for (int i = 0; i < count; i++) {
View view = getChildAt(i);
if (view instanceof TextView) {
((TextView) view).setTextColor(COLOR_TEXT_NORMAL);
}
}
}
/**
* 指示器随着ViewPager的滑动而滚动
*/
private void scroll(int position, float offset) {
int tabWidth = getScreenWidth() / mTabVisiableCount;
// 初始化三角下标的偏移
mTranslationX = (int) (tabWidth * (position + offset));
if (offset > 0 && position >= (mTabVisiableCount - 2)&&getChildCount()>mTabVisiableCount) {
if (mTabVisiableCount != 1) {
this.scrollTo((int) ((position - (mTabVisiableCount - 2)) * tabWidth + offset
* tabWidth), 0);
} else {
this.scrollTo((int) ((position + offset) * tabWidth), 0);
}
}
invalidate();
}
/**
* 设置布局中的一些属性，如果设置了setTabTitles()测布局中的View无效
*/
@Override
protected void onFinishInflate() {
// TODO Auto-generated method stub
super.onFinishInflate();
int count = getChildCount();
if (count == 0) {
return;
}
for (int i = 0; i < count; i++) {
View view = getChildAt(i);
LayoutParams lp = (LayoutParams) view.getLayoutParams();
lp.weight = 0;
lp.width = getScreenWidth() / mTabVisiableCount;
view.setLayoutParams(lp);
}
// 设置点击事件
setItemClickListener();
}
}
使用方法：
package com.wang.demo_viewpagerindictor;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import com.wang.demo_viewpagerindictor.fragment.VpSimpleFragment;
import com.wang.demo_viewpagerindictor.view.ViewPagerIndicator;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.PagerTabStrip;
import android.support.v4.view.ViewPager;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends FragmentActivity {
private ViewPager vp;
private ViewPagerIndicator vp_indicator;
private ArrayList fgs;
private String[] titleStr={"新闻1","新闻1","新闻2","新闻3","新闻4","新闻5","新闻6","新闻7","新闻8","新闻9"};
private List titles;
private FragmentPagerAdapter adapter;
//PagerTabStrip pg;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
//设置标题
vp_indicator.setTabItemTitles(titles);
vp.setAdapter(adapter);
//设置相关联的ViewPager
vp_indicator.setViewPager(vp, 0);
}
private void initView() {
vp=(ViewPager) findViewById(R.id.vp);
vp_indicator=(ViewPagerIndicator) findViewById(R.id.vp_indicator);
}
private void initData() {
titles=Arrays.asList(titleStr);
fgs=new ArrayList();
for(String title:titles){
VpSimpleFragment fg=VpSimpleFragment.newInstance(title);
fgs.add(fg);
}
adapter=new FragmentPagerAdapter(getSupportFragmentManager()) {
@Override
public int getCount() {
return fgs.size();
}
@Override
public Fragment getItem(int position) {
// TODO Auto-generated method stub
return fgs.get(position);
}
};
}
}
源码下载