我正在使用Android Studio 1.51。 在我的AndroidManifest.xml中，我在PuzzleView活动中收到错误，出现以下错误：
PuzzleView没有默认构造函数 PuzzleView不能分配给android.app.Activity。
这是我的AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="mycanvas.example.com.mycanvas"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MyCanvas"
android:label="@string/title_activity_my_canvas" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".PuzzleView"
android:label="@string/title_activity_my_canvas" >
</activity>
</application>
</manifest>
这是我的PuzzleView.java
package mycanvas.example.com.mycanvas;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Paint.FontMetrics;
import android.graphics.Paint.Style;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AnimationUtils;
public class PuzzleView extends View {
private static final String TAG = "MyCanvas";
//private final Game game;
private float width; //width of one tile
private float height; //height of one tile
private int selX; // X index of selection
private int selY; // Y index of selection
private final Rect selRect = new Rect();
public PuzzleView(Context context, AttributeSet attrs) {
super(context,attrs);
setFocusable(true);
setFocusableInTouchMode(true);
}
public PuzzleView(Context context) {
super(context);
//this.game = (Game) context;
setFocusable(true);
setFocusableInTouchMode(true);
}
public PuzzleView(Context context, AttributeSet attrs, int defStyle) {
super(context,attrs,defStyle);
setFocusable(true);
setFocusableInTouchMode(true);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
width = w / 9f;
height = h / 9f;
getRect(selX, selY, selRect);
Log.d(TAG, "onSizeChanged: width " + width + ", height " + height);
super.onSizeChanged(w, h, oldw, oldh);
}
private void getRect(int x, int y, Rect rect) {
rect.set((int)(x * width), (int)(y * height), (int) (x * width + width), (int) (y * height + height));
}
@Override
protected void onDraw(Canvas canvas) {
//Draw the background...
Paint background = new Paint();
background.setColor(getResources().getColor(R.color.puzzle_background));
canvas.drawRect(0, 0, getWidth(), getHeight(), background);
// Draw the board...
// Define colors for the grid lines
Paint dark = new Paint();
dark.setColor(getResources().getColor(R.color.puzzle_dark));
Paint hilite = new Paint();
hilite.setColor(getResources().getColor(R.color.puzzle_hilite));
Paint light = new Paint();
light.setColor(getResources().getColor(R.color.puzzle_light));
// Draw the minor grid lines
for (int i = 0; i < 9; i++) {
canvas.drawLine(0, i * height, getWidth(), i * height, light);
canvas.drawLine(0, i * height + 1, getWidth(), i * height + 1, hilite);
canvas.drawLine(i * width, 0, i * width, getHeight(), light);
canvas.drawLine(i * width + 1, 0, i * width + 1, getHeight(), hilite);
}
// Draw the major grid lines
for (int i = 0; i < 9; i++) {
if ( i % 3 != 0)
continue;
canvas.drawLine(0, i * height, getWidth(), i * height, dark);
canvas.drawLine(0, i * height + 1, getWidth(), i * height + 1, hilite);
canvas.drawLine(i * width, 0, i * width, getHeight(), dark);
canvas.drawLine(i * width + 1, 0, i * width + 1, getHeight(), hilite);
}
// Draw the numbers...
// Define color and style for numbers
Paint foreground = new Paint(Paint.ANTI_ALIAS_FLAG);
foreground.setColor(getResources().getColor(R.color.puzzle_foreground));
foreground.setStyle(Style.FILL);
foreground.setTextSize(height * 0.75f);
foreground.setTextScaleX(width / height);
foreground.setTextAlign(Paint.Align.CENTER);
// Draw the number in the center of the tile
FontMetrics fm = foreground.getFontMetrics();
//Centering in X; use alignment (and X at midpoint)
float x = width / 2;
//Centering in Y; measure ascent/descent first
float y = height / 2 - (fm.ascent + fm.descent) / 2;
for (int i = 0; i < 9; i++) {
for(int j = 0; j<9; j++) {
//canvas.drawText(this.game.getTileString(i, j), i * width + x, j * height + y, foreground);
canvas.drawText("X", i * width + x, j * height + y, foreground);
}
}
// Draw the hints...
//Pick a hint color based on #moves left
// Paint hint = new Paint();
// int c[] = { getResources().getColor(R.color.puzzle_hint_0),
// getResources().getColor(R.color.puzzle_hint_1),
// getResources().getColor(R.color.puzzle_hint_1), };
// Rect r = new Rect();
// for (int i = 0; i<9; i++) {
// for (int j=0; j<9;j++) {
// int movesleft = 9; //9 - game.getUsedTiles(i, j).length;
// if(movesleft < c.length) {
// getRect(i, j, r);
// hint.setColor(c[movesleft]);
// canvas.drawRect(r, hint);
// }
// }
// }
// Draw the selection...
Log.d(TAG, "selRect=" + selRect);
Paint selected = new Paint();
selected.setColor(getResources().getColor(R.color.puzzle_selected));
canvas.drawRect(selRect, selected);
}
@Override
public boolean onKeyDown(int keyCode,KeyEvent event) {
Log.d(TAG, "onKeyDown: keyCode=" + keyCode + ", event=" + event);
switch (keyCode) {
case KeyEvent.KEYCODE_DPAD_UP:
select(selX, selY -1);
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
select(selX, selY + 1);
break;
case KeyEvent.KEYCODE_DPAD_LEFT:
select(selX - 1, selY);
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
select(selX + 1, selY);
break;
case KeyEvent.KEYCODE_0:
case KeyEvent.KEYCODE_SPACE: setSelectedTile(0); break;
case KeyEvent.KEYCODE_1: setSelectedTile(1); break;
case KeyEvent.KEYCODE_2: setSelectedTile(2); break;
case KeyEvent.KEYCODE_3: setSelectedTile(3); break;
case KeyEvent.KEYCODE_4: setSelectedTile(4); break;
case KeyEvent.KEYCODE_5: setSelectedTile(5); break;
case KeyEvent.KEYCODE_6: setSelectedTile(6); break;
case KeyEvent.KEYCODE_7: setSelectedTile(7); break;
case KeyEvent.KEYCODE_8: setSelectedTile(8); break;
case KeyEvent.KEYCODE_9: setSelectedTile(9); break;
case KeyEvent.KEYCODE_ENTER:
case KeyEvent.KEYCODE_DPAD_CENTER:
//game.showKeypadOrError(selX, selY);
break;
default:
return super.onKeyDown(keyCode, event);
}
return true;
}
private void select(int x, int y) {
invalidate(selRect);
selX = Math.min(Math.max(x, 0), 8);
selY = Math.min(Math.max(y, 0), 8);
getRect(selX, selY, selRect);
invalidate(selRect);
}
// @Override
// public boolean onTouchEvent(MotionEvent event){
// if (event.getAction() != MotionEvent.ACTION_DOWN)
// return super.onTouchEvent(event);
//
// select((int) (event.getX() / width), (int)(event.getY() / height));
// //game.showKeypadOrError(selX, selY);
// Log.d(TAG, "onTouchEvent: x " + selX + ", y " + selY);
// return true;
// }
//
public void setSelectedTile(int tile) {
//if (game.setTileIfValid(selX, selY, tile)) {
// invalidate(); //may change hints
//} else {
// Number is not valid for this tile
Log.d(TAG, "setSelectedTile: invalid: " + tile);
//startAnimation(AnimationUtils.loadAnimation(game, R.anim.shake));
//}
}
}
这是MyCanvas.java：
package mycanvas.example.com.mycanvas;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.Direction;
import android.graphics.Rect;
import android.util.Log;
import android.view.Menu;
import android.view.View;
public class MyCanvas extends Activity {
private static final String TAG = "MyCanvas";
private PuzzleView puzzleView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(new GraphicsView(this));
puzzleView = new PuzzleView(this);
setContentView(puzzleView);
puzzleView.requestFocus();
}
static public class GraphicsView extends View {
private Path circle = new Path();
private final Rect rect = new Rect(); //Circle circle = new Circle();
//private final Circel circle = new Circ();
private Paint cPaint, tPaint, myPaint, background;
private int width = 0, height = 0;
private static final String QUOTE = "Now is the time for all " +
"good men to come to the aid of their country.";
private static final String QUOTE2 = "This is just a teaser of the kind " +
"of graphics ANDROID can display. Keep exploring the Graphics API.";
public GraphicsView(Context context) {
super(context);
background = new Paint();
background.setColor(Color.YELLOW);
}
@Override
protected void onDraw(Canvas canvas) {
// Drawing commands go here
Log.i(TAG, "GraphicsView - onDraw()");
//background.setColor(getResources().getColor(R.color.puzzle_background));
rect.set(10, 10, 210, 210);
//cPaint.setColor(Color.LTGRAY);
//circle.addCircle(150, 150, 100, Direction.CW);
//canvas.drawPath(circle, cPaint);
myPaint = new Paint();
myPaint.setColor(Color.rgb(0, 0, 0));
myPaint.setStrokeWidth(10);
cPaint = new Paint();
cPaint.setColor(Color.YELLOW);
cPaint.setStrokeWidth(10);
tPaint = new Paint();
tPaint.setColor(Color.BLACK);
tPaint.setStrokeWidth(10);
canvas.drawRect(rect, myPaint);
//draw a circle on the CANVAS
canvas.drawCircle(150, 150, 30, cPaint);
//add a circle to the PATH
circle.addCircle(250, 250, 100, Direction.CW);
canvas.drawPath(circle, cPaint);
canvas.drawTextOnPath(QUOTE2, circle, 0, 20, tPaint);
canvas.rotate(30);
canvas.drawText("Watch the ANDROID CANVAS !!!!", 300, 300, tPaint);
//canvas.rotate(120);
//canvas.drawText("Watch the ANDROID CANVAS !!!!", 450, 450, tPaint);
//canvas.drawRect(0, 0, getWidth(), getHeight(), background);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
答案 0 :(得分：1)
你的Puzzleview扩展视图它不是一个活动.. MyCanvas扩展了Activity类..你需要将MyCanvas添加到清单而不是PuzzleView。
答案 1 :(得分：0)
你宣布了
<activity
android:name=".PuzzleView"
android:label="@string/title_activity_my_canvas" >
</activity>
即使PuzzleView不是Activity。
只需将其更改为MyCanvas，即实际的Activity
<activity
android:name=".MyCanvas"
android:label="@string/title_activity_my_canvas" >
</activity>
答案 2 :(得分：0)
PuzzleView正在扩展视图类，显然它不能分配给一个活动。因此，要删除错误，请在AndroidManifest中进行以下更正：
<activity
android:name=".MyCanvas"
android:label="@string/title_activity_my_canvas" >
</activity>
android:name表示扩展activty的类的名称，在您的情况下显然是MyCanvas