android基礎--自定義View
1.自定義view繪製字串
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.FontMetrics;
import android.os.Bundle;
import android.view.Display;
import android.view.View;
public class Font extends Activity {
public int mScreenWidth = 0;
public int mScreenHeight = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
setContentView(new FontView(this));
// 獲取螢幕寬高
Display display = getWindowManager().getDefaultDisplay();
mScreenWidth = display.getWidth();
mScreenHeight = display.getHeight();
super.onCreate(savedInstanceState);
}
class FontView extends View {
public final static String STR_WIDTH = "獲取字串寬為：";
public final static String STR_HEIGHT = "獲取字型高度為：";
Paint mPaint = null;
public FontView(Context context) {
super(context);
mPaint = new Paint();
}
@Override
protected void onDraw(Canvas canvas) {
//設定字串顏色
mPaint.setColor(Color.WHITE);
canvas.drawText("當前螢幕寬" + mScreenWidth, 0, 30, mPaint);
canvas.drawText("當前螢幕高"+ mScreenHeight, 0, 60, mPaint);
//設定字型大小
mPaint.setColor(Color.RED);
mPaint.setTextSize(18);
canvas.drawText("字型大小為18", 0, 90, mPaint);
//消除字型鋸齒
mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
canvas.drawText("消除字型鋸齒後", 0, 120, mPaint);
//獲取字串寬度
canvas.drawText(STR_WIDTH + getStringWidth(STR_WIDTH), 0, 150, mPaint);
//獲取字型高度
canvas.drawText(STR_HEIGHT + getFontHeight(), 0, 180, mPaint);
//從string.xml讀取字串繪製
mPaint.setColor(Color.YELLOW);
canvas.drawText(getResources().getString(R.string.string_font), 0, 210, mPaint);
super.onDraw(canvas);
}
/*** 獲取字串寬
* @param str
* @return*/
private int getStringWidth(String str) {
return (int) mPaint.measureText(STR_WIDTH);
}
/** 獲取字型高度 */
private int getFontHeight() {
FontMetrics fm = mPaint.getFontMetrics();
return (int)Math.ceil(fm.descent - fm.top) + 2;
}
}
}
2.繪製無規則幾何圖形
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;
public class Geometry extends Activity {
public int mScreenWidth = 0;
public int mScreenHeight = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
setContentView(new GeometryView(this));
super.onCreate(savedInstanceState);
}
class GeometryView extends View {
Paint mPaint = null;
public GeometryView(Context context) {
super(context);
mPaint = new Paint();
mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//設定畫布顏色 也就是背景顏色
canvas.drawColor(Color.WHITE);
mPaint.setColor(Color.BLACK);
canvas.drawText("繪製無規則幾何圖形喔！！！", 150, 30, mPaint);
//繪製一條線
mPaint.setColor(Color.BLACK);
mPaint.setStrokeWidth(4);
canvas.drawLine(0, 0, 100, 100, mPaint);
//繪製一個矩形
mPaint.setColor(Color.YELLOW);
canvas.drawRect(0, 120, 100, 200, mPaint);
//繪製一個圓形
mPaint.setColor(Color.BLUE);
canvas.drawCircle(80, 300, 50, mPaint);
//繪製一個橢圓
mPaint.setColor(Color.CYAN);
canvas.drawOval(new RectF(300,370,120,100), mPaint);
//繪製多邊形
mPaint.setColor(Color.BLACK);
Path path = new Path();
path.moveTo(150+5 , 400 -50);
path.lineTo(150+45, 400 - 50);
path.lineTo(150+30, 460 - 50);
path.lineTo(150+20, 460 - 50);
path.close();
canvas.drawPath(path, mPaint);
}
}
}
3.圖片的繪製以及旋轉縮放的實現
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
public class Image extends Activity {
ImageView imageView = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
imageView = new ImageView(this);
setContentView(R.layout.image);
LinearLayout ll = (LinearLayout) findViewById(R.id.iamgeid);
ll.addView(imageView);
// 向左移動
Button botton0 = (Button) findViewById(R.id.buttonLeft);
botton0.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setPosLeft();
}
});
// 向右移動
Button botton1 = (Button) findViewById(R.id.buttonRight);
botton1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setPosRight();
}
});
// 左旋轉
Button botton2 = (Button) findViewById(R.id.buttonRotationLeft);
botton2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setRotationLeft();
}
});
// 右旋轉
Button botton3 = (Button) findViewById(R.id.buttonRotationRight);
botton3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setRotationRight();
}
});
// 縮小
Button botton4 = (Button) findViewById(R.id.buttonNarrow);
botton4.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setNarrow();
}
});
// 放大
Button botton5 = (Button) findViewById(R.id.buttonEnlarge);
botton5.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
imageView.setEnlarge();
}
});
super.onCreate(savedInstanceState);
}
class ImageView extends View {
Paint mPaint = null;
Bitmap bitMap = null;
Bitmap bitMapDisplay = null;
int m_posX = 120;
int m_posY = 50;
int m_bitMapWidth = 0;
int m_bitMapHeight = 0;
Matrix mMatrix = null;
float mAngle = 0.0f;
float mScale = 1f;//1為原圖的大小
public ImageView(Context context) {
super(context);
mPaint = new Paint();
mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
bitMap = BitmapFactory.decodeResource(this.getResources(),
R.drawable.image);
bitMapDisplay = bitMap;
mMatrix = new Matrix();
// 獲取圖片寬高
m_bitMapWidth = bitMap.getWidth();
m_bitMapHeight = bitMap.getHeight();
}
// 向左移動
public void setPosLeft() {
m_posX -= 10;
}
// 向右移動
public void setPosRight() {
m_posX += 10;
}
// 向左旋轉
public void setRotationLeft() {
mAngle--;
setAngle();
}
// 向右旋轉
public void setRotationRight() {
mAngle++;
setAngle();
}
// 縮小圖片
public void setNarrow() {
if (mScale > 0.5) {
mScale -= 0.1;
setScale();
}
}
// 放大圖片
public void setEnlarge() {
if (mScale < 2) {
mScale += 0.1;
setScale();
}
}
// 設定縮放比例
public void setAngle() {
mMatrix.reset();
mMatrix.setRotate(mAngle);
bitMapDisplay = Bitmap.createBitmap(bitMap, 0, 0, m_bitMapWidth,
m_bitMapHeight, mMatrix, true);
}
// 設定旋轉比例
public void setScale() {
mMatrix.reset();
//float sx X軸縮放
//float sy Y軸縮放
mMatrix.postScale(mScale, mScale);
bitMapDisplay = Bitmap.createBitmap(bitMap, 0, 0, m_bitMapWidth,
m_bitMapHeight, mMatrix, true);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(bitMapDisplay, m_posX, m_posY, mPaint);
invalidate();
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/iamgeid"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button android:id="@+id/buttonLeft"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="圖片向左移動"
/>
<Button android:id="@+id/buttonRight"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="圖片向右移動"
/>
<Button android:id="@+id/buttonRotationLeft"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="圖片左旋轉"
/>
<Button android:id="@+id/buttonRotationRight"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="圖片右旋轉"
/>
<Button android:id="@+id/buttonNarrow"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="圖片縮小"
/>
<Button android:id="@+id/buttonEnlarge"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:text="圖片放大"
/>
</LinearLayout>
4.播放frame動畫
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
public class FramAnimation extends Activity {
public final static int ANIM_COUNT = 4;
@Override
protected void onCreate(Bundle savedInstanceState) {
setContentView(new FramView(this));
super.onCreate(savedInstanceState);
}
class FramView extends View {
Bitmap[] bitmap = new Bitmap[ANIM_COUNT];
Bitmap display = null;
Paint paint = null;
long startTime = 0;
int playID = 0;
public FramView(Context context) {
super(context);
for (int i = 0; i < ANIM_COUNT; i++) {
bitmap[i] = BitmapFactory.decodeResource(this.getResources(), R.drawable.hero_a + i);
}
display = bitmap[0]; paint = new Paint();
startTime = System.currentTimeMillis();
}
@Override protected void onDraw(Canvas canvas) {
super.onDraw(canvas); paint.setColor(Color.WHITE);
canvas.drawText("播放動畫中...", 100, 30, paint);
long nowTime = System.currentTimeMillis();
if (nowTime - startTime >= 500) {
startTime=nowTime;
playID++;
if (playID >= ANIM_COUNT) {
playID = 0;
}
canvas.drawBitmap(bitmap[playID], 100, 100, paint);
}
invalidate();
}
}
}