本demo技术要点

自定义快速索引控件ViewPager有效的禁止左右滑动Fragment抽取懒加载基类,且只加载一次 感谢开源库SwipeMenuListView

效果图

快速索引控件.

package cn.evun.view; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import cn.evun.javebean.Cheeses; /** * 自定义快速索引 */ public class QuickIndexBar extends View { private Paint paint; private float cellWidth; private float cellHeight; public QuickIndexBar(Context context, AttributeSet attrs) { super(context, attrs); init(); } private void init() { paint = new Paint(); paint.setColor(Color.GRAY); paint.setTextSize(30); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // canvas.drawText("#",10f,20f,paint); // canvas.drawText("#",10f,50f,paint); // canvas.drawText("#",10f,80f,paint); // canvas.drawText("#",10f,110f,paint); // canvas.drawText("#",10f,140f,paint); for (int i = 0; i < Cheeses.LETTERS.length; i++) { String letter = Cheeses.LETTERS[i]; Rect rect = new Rect(); //获取不同的字母的宽高 //将字母放入一个矩形容器中,矩形容器的宽高就是字母的宽高 //获取文字边界 paint.getTextBounds(letter, 0, 1, rect); //矩形的宽高就是文本的宽高 int textWidth = rect.width(); int textHeight = rect.height(); float x = cellWidth * 0.5f - textWidth * 0.5f; float y = cellHeight * 0.5f + textHeight * 0.5f + i * cellHeight; canvas.drawText(letter, x, y, paint); } } //获取cellWidth和cellHeight @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); //获取当前控件的测量宽高 cellWidth = this.getMeasuredWidth(); cellHeight = this.getMeasuredHeight() * 1.0f / Cheeses.LETTERS.length; } //当前索引 private int currentIndex = -1; //上一个索引 private int lastIndex = -1; @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: case MotionEvent.ACTION_MOVE: if (listener != null) { //每次滑动前,将当前索引赋值给上一个索引 lastIndex = currentIndex; //目的:找到触摸的位置对应的letter float y = event.getY(); //修改当前索引 currentIndex = (int) (y / cellHeight); if (currentIndex > Cheeses.LETTERS.length - 1) { currentIndex = Cheeses.LETTERS.length - 1; } else if (currentIndex < 0) { currentIndex = 0; } if (lastIndex != currentIndex) { String letter = Cheeses.LETTERS[currentIndex]; // Log.i("test", "letter:" + letter); listener.onLetterChanged(letter); } } break; case MotionEvent.ACTION_UP: if(listener!=null){ listener.onLetterDismiss(); } break; } //想要处理事件 return true; } private OnLetterChangedListener listener; public interface OnLetterChangedListener { void onLetterChanged(String letter); void onLetterDismiss(); } public void setOnLetterChangedListener(OnLetterChangedListener listener) { this.listener = listener; } }

ViewPager有效的禁止左右滑动

package cn.evun.view; import android.content.Context; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.view.MotionEvent; /** */ public class NoScrollViewPager extends ViewPager { private boolean canScroll =true; public NoScrollViewPager(Context context) { super(context); } public NoScrollViewPager(Context context, AttributeSet attrs) { super(context, attrs); } @Override public boolean onTouchEvent(MotionEvent ev) { return this.canScroll&&super.onTouchEvent(ev); } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { return this.canScroll&&super.onInterceptTouchEvent(ev); } public void isCanScroll(boolean b){ this.canScroll =b; } }

源码传送

下载 Github源码