Toast 自定义显示位置,toast和通讯录的a-z 一起走 部分代码

Toast的显示位置可以我们自己设置，通过如下命令：

toast = Toast.makeText(getContext(), "" + (char) ('A' + position),Toast.LENGTH_SHORT);//可以控制toast显示的位置toast.setGravity(Gravity.LEFT, xoffset, yoffset);toast.show();

同时我们通过toast.cancle（）可以用来取消一个toast，这在我们滑动到下一个字母的时候，就可以取消掉上一个字母的显示。

if(toast!=null)toast.cancel();

package com.zqxue.Review151222;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.util.Log;import android.util.TypedValue;import android.view.Gravity;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.widget.LinearLayout;import android.widget.TextView;import android.widget.Toast;/** * Created by XUE on 2015/12/22. */public class SimpleView extends LinearLayout {    private Paint paint;    private float stopY;    private Toast toast;    public SimpleView(Context context) {        super(context);    }    public SimpleView(Context context, AttributeSet attrs) {        super(context, attrs);        init(context,attrs);    }    public void init(Context context,AttributeSet attrs){        paint = new Paint();        paint.setColor(Color.RED);        for (int i = 0; i < 26; i++) {            TextView textView = new TextView(context);            String text = Character.toString((char)('A'+i));            textView.setText(text);            ViewGroup.LayoutParams layoutParams = new LayoutParams(                    ViewGroup.LayoutParams.MATCH_PARENT,                    0,                    1            );            textView.setLayoutParams(layoutParams);            //textSize            int height = getHeight();            int textSize = height/26-2;            textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, textSize);            textView.setGravity(Gravity.RIGHT);            addView(textView);        }    }    private int currentPosition=-1;    @Override    public boolean onTouchEvent(MotionEvent event) {        boolean ret = false;        int action = event.getAction();        float ex = event.getX();        float ey = event.getY();        stopY=ey;        int position = -1;        String type = "";        switch (action){            case MotionEvent.ACTION_DOWN:                type ="DOWN";                currentPosition=-1;                //toast                if(toast!=null)toast.cancel();                toast = Toast.makeText(getContext(), "" + (char) ('A' + position),                        Toast.LENGTH_SHORT);                Log.d("151222MY","LONG="+Toast.LENGTH_LONG+"  SHORT="+Toast.LENGTH_SHORT+ ex+""+ey);                //可以控制toast显示的位置                //toast.setGravity(Gravity.LEFT, right + child.getWidth() + 200, bottom - getHeight() / 2);                toast.setGravity(Gravity.LEFT, getWidth() - 150, (int) ey - getHeight() / 2);                toast.show();                ret=true;                break;            case MotionEvent.ACTION_MOVE:                int childCount = getChildCount();                for (int i = 0; i < childCount; i++) {                    View child = getChildAt(i);                    int top = child.getTop();                    int left = child.getLeft();                    int right = child.getRight();                    int bottom = child.getBottom();                    if(top<=ey&&left<=ex){                        if(right>=ex&&bottom>=ey){                            position = i;                        }                    }                    if(position>-1&&currentPosition!=position){                        Log.d("151222MY","click "+position);                        Log.d("151222MY","click"+(char)('A'+position));                        currentPosition=position;                        if(toast!=null)toast.cancel();                        toast = Toast.makeText(getContext(), "" + (char) ('A' + position),                                Toast.LENGTH_SHORT);                        Log.d("151222MY","LONG="+Toast.LENGTH_LONG+"  SHORT="+Toast.LENGTH_SHORT);                        //可以控制toast显示的位置                        //toast.setGravity(Gravity.LEFT, right + child.getWidth() + 200, bottom - getHeight() / 2);                        toast.setGravity(Gravity.LEFT, getWidth()-150, (int)ey - getHeight() / 2);                        toast.show();                    }                }                type="MOVE";                break;            case MotionEvent.ACTION_UP:                type="UP";                break;        }        //Log.d("151222MY", type);        return ret;    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawLine(0, 0, 300, stopY, paint);        Log.d("151222MY","onDraw");    }}