android 验证码 (canvas)

activity:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LinearLayout linearLayout = new LinearLayout(this);
VerifyCodeView vc = new VerifyCodeView(this,6);
TextView textView = new TextView(this);
textView.setText("验证码:");
EditText mInCode = new EditText(this);
vc.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
v.postInvalidate();//重新调用VerifyCodeView的构造方法,更新验证码
Toast.makeText(getApplicationContext(),"updat code",Toast.LENGTH_LONG).show();
}
});
linearLayout.addView(textView);
linearLayout.addView(mInCode);
linearLayout.addView(vc);
setContentView(linearLayout);
}

view:

private Character[] codes = {'q','w','e','r','t','y','u','i'
,'o','p','a','s','d','f','g','h'
,'j','k','l','z','x','c','v','b'
,'n','m','1','2','3','4','5','6'
,'7','8','9','0'};
private Character[] vcode;

public VerifyCodeView(Context context) {
super(context);
vcode = new Character[4];//定义验证码的长度
}

public VerifyCodeView(Context context, int codeSize) {
super(context);
vcode = new Character[codeSize];//定义验证码的长度
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
vcode = getCodes(codes);
Paint pen = new Paint();
pen.setColor(Color.WHITE);
int mwidth = getWidth();
canvas.drawRect(mwidth*2/3,10.0f,mwidth-20,100.0f,pen);
Random r = new Random(100);
int padding = 1;
for (int i = 0; i < vcode.length; i++) {
pen.setColor(Color.rgb(r.nextInt(),r.nextInt(),r.nextInt()));
pen.setTextSize(60);
//canvas.drawText(new char[]{'a','c','b','d','1','2','e'},0,7,mwidth*2/3+10,70.0f,pen);
//String text = "h"+r.nextInt()+"e"+r.nextInt()+"l";
canvas.drawText(vcode[i].toString(),mwidth*2/3+padding,70.0f,pen);
padding = padding + 35;
}
}

public Character[] getCodes(Character[] codes){
Random rd = new Random();
for (int i = 0; i < vcode.length; i++) {
vcode[i] = codes[rd.nextInt(36)];
}
return vcode;
}