Android图形编程基本概念

1. 颜色对象

   Color 类

   int color = Color.bule    //蓝色

   int color = Color.argb(255,255,255,255);        //透明度，红，绿，蓝

   在XML文件中定义颜色

2. 画笔对象

   Paint 类

   Paint.setColor(Color.blue);

    

3. 画布对象

   Canvas 类

   Canvas.drawCircle(300, 400, 100, paint);

    

自定义View的基本实现方法

1. 定义一个类，继承View
2. 复写View中的onDraw()方法
3. 在onDraw()中使用Canvas和Paint绘制图形

    

   矩形。圆形、空心、实心、线、文字、……

@Override

    protected void onDraw(Canvas canvas) {

        Paint paint = new Paint();

        paint.setARGB(255, 0, 255, 0);

        paint.setStyle(Paint.Style.STROKE);// 空心

        paint.setStrokeWidth(10);// 边的宽度

        canvas.drawRect(100, 100, 500, 500, paint);// 矩形

 

        paint.setStyle(Paint.Style.FILL);// 实心

        paint.setColor(Color.CYAN);

        canvas.drawCircle(500, 500, 100, paint);// 圆形

 

        paint.setTextSize(100);

        paint.setColor(Color.BLUE);

        canvas.drawText("Apple ggGG", 50, 800, paint);

 

        paint.setColor(Color.RED);

        paint.setStrokeWidth(5);// 边的宽度

        canvas.drawLine(0, 800, 720, 800, paint);

 

        canvas.drawBitmap(BitmapFactory.decodeResource(getResources(),

                R.drawable.ic_launcher), 200, 200, paint);

 

        super.onDraw(canvas);

    }

 

绘制九宫格

@Override

    protected void onDraw(Canvas canvas) {

        // 首先取得屏幕的宽度和高度

        width = this.getWidth();

        cell_width = width / 9f;

        height = this.getHeight();

        cell_height = height / 9f;

 

        // 首先画出背景

        Paint bgPaint = new Paint();// 用于绘制背景

        bgPaint.setColor(getResources().getColor(R.color.shudu_background));

        canvas.drawRect(0, 0, width, height, bgPaint);

 

        // 画出九宫格

        Paint darkPaint = new Paint();// 暗色

        darkPaint.setColor(getResources().getColor(R.color.shudu_dark));

        Paint lightPaint = new Paint();// 亮色

        darkPaint.setColor(getResources().getColor(R.color.shudu_light));

        Paint hilitePaint = new Paint();// 线条

        darkPaint.setColor(getResources().getColor(R.color.shudu_hilite));

        for (int i = 0; i < 9; i++) {

            if (i % 3 == 0) {

                canvas.drawLine(0, i * cell_height, width, i * cell_height,

                        lightPaint);

                canvas.drawLine(i * cell_width, 0, i * cell_width, height,

                        lightPaint);

            } else {

                canvas.drawLine(0, i * cell_height, width, i * cell_height,

                        darkPaint);

                canvas.drawLine(i * cell_width, 0, i * cell_width, height,

                        darkPaint);

            }

            canvas.drawLine(0, i * cell_height + 1, width, i * cell_height + 1,

                    hilitePaint);

            canvas.drawLine(i * cell_width + 1, 0, i * cell_width + 1, height,

                    hilitePaint);

        }

 

        // 绘制文字

        Paint numPaint = new Paint();

        numPaint.setColor(Color.BLUE);

        numPaint.setStyle(Paint.Style.STROKE);

        numPaint.setTextSize(cell_height * 0.25f);

        numPaint.setTextAlign(Paint.Align.CENTER);

        float x = cell_width / 2;

        float y = cell_height / 2;

        for (int i = 0; i < 9; i++) {

            for (int j = 0; j < 9; j++) {

                canvas.drawText("" + i + "," + j, i * cell_width

                        + x, j * cell_height + y, numPaint);

            }

        }

 

        super.onDraw(canvas);

    }

文字居中显示

FontMtrics类

FontMetrics fontMetrics = paint.get FontMetrics();

        FontMetrics fm = numPaint.getFontMetrics();

        float x = cell_width / 2;

        float y = cell_height / 2 - (fm.ascent + fm.descent) / 2;

显示数据

把逻辑处理放在Activity外部，新建一个类

package com.arlen.android.game.shudu03;

 

public class Game {

    private final String str = "450890000000000000008700090607005030090020040040900102070006300000000000000048016";

    private int shuduku[] = new int[81];

 

    public Game() {

        shuduku = fromPuzzleString(str);

    }

 

    private int getTitle(int x, int y) {

        return shuduku[y * 9 + x];

    }

 

    public String getTitleString(int x, int y) {

        int v = getTitle(x, y);

        if (v == 0) {

            return "";

        } else {

            return String.valueOf(v);

        }

    }

 

    protected int[] fromPuzzleString(String src) {

        int sudu[] = new int[src.length()];

        for (int i = 0; i < sudu.length; i++) {

            sudu[i] = src.charAt(i) - '0';

        }

        return sudu;

    }

}

在View中调用

        for (int i = 0; i < 9; i++) {

            for (int j = 0; j < 9; j++) {

                canvas.drawText(game.getTitleString(i, j), i * cell_width + x,

                        j * cell_height + y, numPaint);

            }

        }

单点触摸事件

在为初始化数字的空格中点击，然后输入数字

public Boolean onTouchEvent(MotionEvent event){

//获取事件的类型

event.getAction();

//获取点击坐标

Event.getX();

Event.getY();

}

 

 

        // 生成一个layoutInflater对象

        LayoutInflater layoutInflater = LayoutInflater.from(this.getContext());

        // 使用layoutInflater对象更具一个布局文件生成一个view对象

        View layoutView = layoutInflater.inflate(R.layout.dialog, null);

        // 从生成好的textView中取出相应的控件

        TextView textView = (TextView) layoutView

                .findViewById(R.id.textViewUsedId);

        // 设置textView的内容

        textView.setText(sb.toString());

        // 生成一个对话框的builder对象

        AlertDialog.Builder builder = new AlertDialog.Builder(this.getContext());

        // 设置地对话框所要显示的内容

        builder.setView(layoutView);

        // 生成对话框对象并将其显示出来

        AlertDialog dialog = builder.create();

        dialog.show();

 

碰撞检测

用户点击屏幕之后，确定用户点击的位置属于哪一个格子

取得用户点击的坐标，判断是否在startX、startY与stopX、stopY之间

    @Override

    public boolean onTouchEvent(MotionEvent event) {

 

        if (event.getAction() != MotionEvent.ACTION_DOWN) {

            return super.onTouchEvent(event);

        }

 

        int selectX = (int) (event.getX() / cell_width);

        int selectY = (int) (event.getY() / cell_height);

 

        int used[] = game.getUsedTileByCoor(selectY, selectY);

        for (int i = 0; i < used.length; i++) {

            System.out.println(used[i]);

        }

        return true;

    }

 

可用数据计算

在每一行、每一列、每一个小的九宫格中已有的数据禁止重复输入，

    //用于计算所有单元格对应的不可用的数据

    public void calculateAllUsedTitles() {

        for (int x = 0; x < 9; x++) {

            for (int y = 0; y < 9; y++) {

                used[x][y] = calculateUsedTiles(x, y);

            }

        }

    }

 

    //取出某一单元格已经不可用的数据

    public int[] getUsedTileByCoor(int x, int y) {

        return used[x][y];

    }

 

    // 计算某一单元格中已经用过的数据

    public int[] calculateUsedTiles(int x, int y) {

        int c[] = new int[9];

 

        for (int i = 0; i < 9; i++) {

            if (i == y) {

                continue;

            }

            int t = getTitle(x, i);

            if (t != 0) {

                c[t - 1] = t;

            }

        }

 

        for (int i = 0; i < 9; i++) {

            if (i == x) {

                continue;

            }

            int t = getTitle(i, y);

            if (t != 0) {

                c[t - 1] = t;

            }

        }

 

        int startX = (x / 3) * 3;

        int startY = (y / 3) * 3;

        for (int i = startX; i < startX + 3; i++) {

            for (int j = startY; j < startY + 3; j++) {

                if (i == x && j == y) {

                    continue;

                }

                int t = getTitle(i, y);

                if (t != 0) {

                    c[t - 1] = t;

                }

            }

        }

 

        // compress

        int nused = 0;

        for (int t : c) {

            if (t != 0) {

                nused++;

            }

        }

 

        int c1[] = new int[nused];

        nused = 0;

        for (int t : c) {

            if (t != 0) {

                c1[nused++] = t;

            }

        }

        return c1;

    }

弹出交互对话框

布局文件

<?xml version="1.0" encoding="utf-8"?>

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/keypad"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:orientation="vertical" >

 

<TableRow>

 

<Button

android:id="@+id/button1"

android:text="1" />

 

<Button

android:id="@+id/button2"

android:text="2" />

 

<Button

android:id="@+id/button3"

android:text="3" />

</TableRow>

 

<TableRow>

 

<Button

android:id="@+id/button4"

android:text="4" />

 

<Button

android:id="@+id/button5"

android:text="5" />

 

<Button

android:id="@+id/button6"

android:text="6" />

</TableRow>

 

<TableRow>

 

<Button

android:id="@+id/button7"

android:text="7" />

 

<Button

android:id="@+id/button8"

android:text="8" />

 

<Button

android:id="@+id/button9"

android:text="9" />

</TableRow>

 

</TableLayout>

根据点击的位置不同，弹出的窗口不同

package com.arlen.android.game.shudu03;

 

import android.app.Dialog;

import android.content.Context;

import android.os.Bundle;

import android.view.View;

 

public class KeyDialog extends Dialog {

 

    // 用来存放代表对话框中按钮的对象

    private final View keys[] = new View[9];

    private final int used[];

 

    // 构造函数的第二个参数保存当前单元格已经用过的数据

    public KeyDialog(Context context, int[] used) {

        super(context);

        this.used = used;

    }

 

    // 当对话框第一次被调用的时候，会调用其onCreate方法

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        // 标题

        this.setTitle("Key Dialog");

        // 为该对话框设置布局文件

        this.setContentView(R.layout.keypad);

        findViews();

 

        // 便利整个used数组

        for (int i = 0; i < used.length; i++) {

            if (used[i] != 0) {

                keys[used[i] - 1].setVisibility(View.INVISIBLE);

            }

        }

    }

 

    private void findViews() {

        keys[0] = findViewById(R.id.button1);

        keys[1] = findViewById(R.id.button2);

        keys[2] = findViewById(R.id.button3);

        keys[3] = findViewById(R.id.button4);

        keys[4] = findViewById(R.id.button5);

        keys[5] = findViewById(R.id.button6);

        keys[6] = findViewById(R.id.button7);

        keys[7] = findViewById(R.id.button8);

        keys[8] = findViewById(R.id.button9);

    }

 

}