自定义View之字母导航控件

xml

<LinearLayout     xmlns:tools="http://schemas.android.com/tools"      android:layout_width="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_height="fill_parent"    android:orientation="vertical"    android:background="#FFF68F"    >    <EditText         android:layout_width="match_parent"        android:layout_height="wrap_content"        android:background="@drawable/round_edittext"        />    <FrameLayout        android:layout_width="match_parent"        android:layout_height="match_parent"       >        <TextView             android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="1"            android:textSize="50sp"            android:layout_gravity="center"            android:gravity="center"            android:id="@+id/mytextview"            android:visibility="invisible"/>        <com.example.uimyviews.MyView             android:layout_width="40dp"            android:layout_height="match_parent"            android:text="2"            android:background="#ffffff"            android:layout_gravity="right"            android:id="@+id/myview"/>    </FrameLayout></LinearLayout>

MainActivity

public class MainActivity extends Activity {    TextView textView;    MyView myView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        textView = (TextView) this.findViewById(R.id.mytextview);        myView = (MyView) this.findViewById(R.id.myview);        myView.setTextview(textView);    }}

MyView

package com.example.uimyviews;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.widget.TextView;public class MyView extends View {    int choose = -1;//选中哪块    TextView textview;    Paint p=new Paint();    String[] str={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","#"};    int width = -1;//view宽    float height = -1;//view高    float singleH = -1;//单个块的高    public MyView(Context context, AttributeSet attrs) {        super(context, attrs);        initPaint();    }    private void initPaint(){        p.setColor(Color.BLACK);        p.setTextSize(30);        p.setAntiAlias(true);//抗锯齿    }    @Override    protected void onDraw(Canvas canvas) {        // TODO Auto-generated method stub        super.onDraw(canvas);        width = getWidth();        height = getHeight();        singleH = height/str.length;        for(int i=0;i<str.length;i++){            if(i != choose){                canvas.drawText(str[i],((float)(width-p.measureText(str[i]))/2),singleH*(i+1),p);            }            else{                p.setColor(Color.RED);                canvas.drawText(str[i],((float)(width-p.measureText(str[i]))/2),singleH*(i+1),p);                p.setColor(Color.BLACK);            }        }    }    @Override    public boolean dispatchTouchEvent(MotionEvent event) {        int e = event.getAction();        float y = (float) event.getY();        //  int÷float=int        choose = (int)((y/height)*str.length);//选中的是第几个,【这个要小心】        switch (e) {        case MotionEvent.ACTION_UP:            textview.setVisibility(View.INVISIBLE);//不可视            choose = -1;            invalidate();            break;        default://move and down            if(choose >= 0 && choose < 27){            textview.setText(str[choose]);            textview.setVisibility(View.VISIBLE);//可视            }            invalidate();            break;        }        return true;    }    public TextView getTextview() {        return textview;    }    public void setTextview(TextView textview) {        this.textview = textview;    }}

效果：