android之簡單好用的本地生成驗證碼並進行驗證

在APP上進行登錄時，爲了防止惡意的頻繁登錄，有時需要先進行驗證碼驗證，然後再進行登錄。目前主流的驗證時通過手機獲取驗證碼進行驗證，但這樣需要綁定手機及個性信息，而有些是不需要通過手機，只需本地生成驗證就好，今天的這個就是使用本地生成的驗證碼。

首先編輯佈局的XML文件，簡單的展示驗證碼的界面，代碼如下：

<RelativeLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
       >
     <LinearLayout 
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:orientation="horizontal"
         android:layout_centerInParent="true"
         > 
    <EditText
        android:id="@+id/vc_code"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        />

    <ImageView
        android:id="@+id/vc_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="center"
        android:layout_gravity="center_vertical"
        />
    <Button
        android:id="@+id/vc_shuaxin" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:text="刷新"
        />
    </LinearLayout>
    </RelativeLayout>   
    <LinearLayout 
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:orientation="vertical"
         > 
     <Button
        android:id="@+id/vc_ok" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="確定"
        />
    </LinearLayout>

在生成驗證碼並以圖片的形式展示中，重點是需要咱們定義生成一個隨機數，然後把它在自定義的圖形中繪製出來，核心類如下（註釋夠詳細，這裏就不再多說）：

public class Code {
    private static final char[] CHARS = {
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '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',
        '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'
    };

    private static Code bpUtil;
    private Code(){};
    public static Code getInstance() {
        if(bpUtil == null)
            bpUtil = new Code();
        return bpUtil;
    }
    //default settings
    private static final int DEFAULT_CODE_LENGTH = 4;//驗證碼的長度  這裏是4位
    private static final int DEFAULT_FONT_SIZE = 60;//字體大小
    private static final int DEFAULT_LINE_NUMBER = 3;//多少條幹擾線
    private static final int BASE_PADDING_LEFT = 20; //左邊距
    private static final int RANGE_PADDING_LEFT = 35;//左邊距範圍值  
    private static final int BASE_PADDING_TOP = 42;//上邊距
    private static final int RANGE_PADDING_TOP = 15;//上邊距範圍值
    private static final int DEFAULT_WIDTH = 200;//默認寬度.圖片的總寬
    private static final int DEFAULT_HEIGHT = 70;//默認高度.圖片的總高
    private  final int DEFAULT_COLOR=0xdf;//默認背景顏色值

    //settings decided by the layout xml
    //canvas width and height
    private int width = DEFAULT_WIDTH;
    private int height = DEFAULT_HEIGHT; 

    //random word space and pading_top
    private int base_padding_left = BASE_PADDING_LEFT;
    private int range_padding_left = RANGE_PADDING_LEFT;
    private int base_padding_top = BASE_PADDING_TOP;
    private int range_padding_top = RANGE_PADDING_TOP;

    //number of chars, lines; font size
    private int codeLength = DEFAULT_CODE_LENGTH;
    private int line_number = DEFAULT_LINE_NUMBER;
    private int font_size = DEFAULT_FONT_SIZE;

    //variables
    private String code;//保存生成的驗證碼
    private int padding_left, padding_top;
    private Random random = new Random();

    private Bitmap createBitmap() {
        padding_left = 0;

        Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888); 
        Canvas c = new Canvas(bp);

        code = createCode();

        c.drawColor(Color.rgb(DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_COLOR));
        Paint paint = new Paint();
        paint.setTextSize(font_size);

        for (int i = 0; i < code.length(); i++) {
            randomTextStyle(paint);
            randomPadding();
            c.drawText(code.charAt(i)+"", padding_left, padding_top, paint);
        }

        for (int i = 0; i < line_number; i++) {
            drawLine(c, paint);
        }

        c.save( Canvas.ALL_SAVE_FLAG );//保存  
        c.restore();//
        return bp;
    }

    public String getCode() {
        return code.toLowerCase();
    }

    public Bitmap getBitmap(){
        return createBitmap();
    }
    private String createCode() {
        StringBuilder buffer = new StringBuilder();
        for (int i = 0; i < codeLength; i++) {
            buffer.append(CHARS[random.nextInt(CHARS.length)]);
        }
        return buffer.toString();
    }

    private void drawLine(Canvas canvas, Paint paint) {
        int color = randomColor();
        int startX = random.nextInt(width);
        int startY = random.nextInt(height);
        int stopX = random.nextInt(width);
        int stopY = random.nextInt(height);
        paint.setStrokeWidth(1);
        paint.setColor(color);
        canvas.drawLine(startX, startY, stopX, stopY, paint);
    }

    private int randomColor() {
        return randomColor(1);
    }

    private int randomColor(int rate) {
        int red = random.nextInt(256) / rate;
        int green = random.nextInt(256) / rate;
        int blue = random.nextInt(256) / rate;
        return Color.rgb(red, green, blue);
    }

    private void randomTextStyle(Paint paint) {
        int color = randomColor();
        paint.setColor(color);
        paint.setFakeBoldText(random.nextBoolean());  //true爲粗體，false爲非粗體
        float skewX = random.nextInt(11) / 10;
        skewX = random.nextBoolean() ? skewX : -skewX;
        paint.setTextSkewX(skewX); //float類型參數，負數表示右斜，整數左斜
    }

    private void randomPadding() {
        padding_left += base_padding_left + random.nextInt(range_padding_left);
        padding_top = base_padding_top + random.nextInt(range_padding_top);
    }
}

最後在MainActivity中調用：

public class MainActivity extends Activity {

    ImageView vc_image; // 顯示驗證碼的圖標
    Button btn_shuaxin, btn_ok; // 確定和刷新按鈕
    String getCode =""; // 獲取驗證碼的值
    EditText etext_code; // 文本框輸入的值用來驗證

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        vc_image=(ImageView)findViewById(R.id.vc_image);
        vc_image.setImageBitmap(Code.getInstance().getBitmap());
        etext_code=(EditText) findViewById(R.id.vc_code);

        getCode=Code.getInstance().getCode(); //獲取顯示的驗證碼

        btn_shuaxin=(Button)findViewById(R.id.vc_shuaxin);
        btn_shuaxin.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                vc_image.setImageBitmap(Code.getInstance().getBitmap());
                getCode=Code.getInstance().getCode();
            }
        });

        btn_ok=(Button)findViewById(R.id.vc_ok);
        btn_ok.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
            String  v_code=etext_code.getText().toString().trim();
            if(v_code==null||v_code.equals("")){
                Toast.makeText(MainActivity.this, "請先驗證",Toast.LENGTH_SHORT).show();
            }else if(!v_code.equals(getCode)){
                Toast.makeText(MainActivity.this, "驗證碼有誤", Toast.LENGTH_SHORT).show();
            }else{
                Toast.makeText(MainActivity.this, "操作成功", Toast.LENGTH_SHORT).show();
            }

            }
        });
      }
    }

此時，一個本地的驗證碼生成驗證就已經出來了，是不是非常的簡單。0.0

Demo地址:http://download.csdn.net/detail/myname_kk/9375823