如何创建一个自定义View
首先我们应该先创建一个工程，工程名字为：checkview
此时的包名：com.example.checkview
接下来我们要创建一个 checkview CheckView.java(activity)
package com.example.checkview.widget.CheckView;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import com.example.checkview.CheckViewUtils;
public class CheckView extends View {
private Paint paint=new Paint();
public int[] checkNum;
public CheckView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
paint.setTextSize(60);
paint.setStrokeWidth(6);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLUE);
int width=getWidth();
int height=getHeight();
int checkNumX=40;
if(checkNum==null){
canvas.drawText("请设置setCheckNum", checkNumX, CheckViewUtils.getY(height), paint);
}else{
for(int i = 0; i< CheckViewUtils.getCheckNumCount(); i++){
canvas.drawText(checkNum[i]+"", checkNumX, CheckViewUtils.getY(height), paint);
checkNumX+=width/5;
}
}
for(int i=0;i<2;i++){
int[] line=CheckViewUtils.getLine(width, height);//获取线条起点和终点
canvas.drawLine(line[0], line[1], line[2], line[3], paint);
}
for(int i=0;i<10;i++){
int[] round=CheckViewUtils.getRound(width, height);//获取小圆点位置
canvas.drawPoint(round[0], round[1], paint);
}
}
public int[] getCheckNum() {//获取验证码
return checkNum;
}
/**
* 该方法必须被调用
* @param checkNum
*/
public void setCheckNum(boolean bl) {
if(bl){
this.checkNum = CheckViewUtils.getCheckNum();//获取验证码
}
}
/**
* 刷新验证码
* invalidate和postInvalidate方法会重新调用onDraw()方法
*/
public void notifyDataSetChanged(){
// invalidate();
setCheckNum(true);
postInvalidate();
}
}
我们需要一个工具类 CheckViewUtils.java(activity)
package com.example.checkview;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import java.util.Random;
public class CheckViewUtils {
private static int roundNum=10;//小圆点默认值
public static int getRoundNum() {
return roundNum;
}
/**
* 设置小圆点数量
* @param roundNum
*/
public static void setRoundNum(int roundNum) {
CheckViewUtils.roundNum = roundNum;
}
public static int getCheckNumCount() {
return checkNumCount;
}
/**
* 设置验证码数量
* @param checkNumCount
*/
public static void setCheckNumCount(int checkNumCount) {
CheckViewUtils.checkNumCount = checkNumCount;
}
private static int checkNumCount=4;//验证码位数
private static Random Rd=new Random();
/**
* 获取验证码
* @return
*/
public static int[] getCheckNum(){
int[] checkNum=new int[checkNumCount];
for(int i=0;i<checkNumCount;i++){
checkNum[i]=(int)(Rd.nextInt(10));
}
return checkNum;
}
/**
* 获取圆点位置
* @param width
* @param height
* @return
*/
public static int[] getRound(int width,int height){
int[] roundArr={0,0};
roundArr[0]=(int)(Rd.nextInt(width));
roundArr[1]=(int)(Rd.nextInt(height));
return roundArr;
}
/**
* 获取线条的起点和终点坐标
* @param width
* @param height
* @return
*/
public static int[] getLine(int width,int height){
int[] lineArr={0,0,0,0};
for(int i=0;i<4;i+=2){
lineArr[i]=(int)(Rd.nextInt(width));
lineArr[i+1]=(int)(Rd.nextInt(height));
}
return lineArr;
}
/**
* 验证是否通过
* @param numString 用户输入数字
* @param checkNum 验证的数字
* @return
*/
public static boolean validationNum(String numString,int[] checkNum){
if(numString.length()!=checkNumCount)
return false;
String checkNumString="";
for(int i=0;i<checkNumCount;i++){
checkNumString+=checkNum[i];
}
if(checkNumString.equals(numString)){
return true;
}else{
return false;
}
}
/**
* 获取Y点坐标
* @param height
* @return
*/
public static int getY(int height){
int y=(int)(Rd.nextInt(height));
if(y>height-60){
y-=60;
}
if(y<60){
y+=60;
}
return y;
}
}
接下来就是主入口activity MainActivity.java(activity)
package com.example.checkview;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private Button btnSubmit;
private com.example.checkview.widget.CheckView.CheckView cv;
private Button btnS;
private EditText et;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnSubmit=(Button) findViewById(R.id.button1);
et=(EditText) findViewById(R.id.et);
cv=(com.example.checkview.widget.CheckView.CheckView) findViewById(R.id.cv);
cv.setCheckNum(true);//设置启用验证码数字,必须设置该属性
btnS=(Button) findViewById(R.id.button2);
btnS.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
cv.notifyDataSetChanged();
}
});
btnSubmit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String etString=et.getText().toString().trim();
int[] checkNum=cv.getCheckNum();
if(CheckViewUtils.validationNum(etString, checkNum)){
Toast.makeText(MainActivity.this, "验证通过", 1).show();
}else{
Toast.makeText(MainActivity.this, "验证失败", 1).show();
}
}
});
}
}
activity_main.xml(layout布局)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >
<com.example.checkview.widget.CheckView.CheckView
android:id="@+id/cv"
android:layout_width="200dip"
android:layout_height="50dip"
/>
<EditText
android:id="@+id/et"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/button1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="验证" />
<Button
android:id="@+id/button2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="刷新" />
</LinearLayout>