我试图将已经绘制到屏幕的位图转换为imageView，以便我可以启用拖动和放大放下它的方法..这是我认为我可以实现这一点的唯一方法。
I尝试将加载的位图（hazardCard）加载到名为cardImage1的imageview中。
代码：
public class PlayScreen extends GameScreen {
// /////////////////////////////////////////////////////////////////////////
// Properties
// /////////////////////////////////////////////////////////////////////////
private Rect backButtonBound;
private Rect hazardCardBound;
private Music screenClickMusic;
/**
* Width and height of the level
*/
// private final float LEVEL_WIDTH = 1000.0f;
//private final float LEVEL_HEIGHT = 1000.0f;
/**
* Define viewports for this layer and the associated screen projection
*/
private ScreenViewport mScreenViewport;
private LayerViewport mLayerViewport;
private Bitmap backgroundBitmap;
private Bitmap backButton;
private Bitmap PlayScreenTitle;
private Bitmap hazardCard;
private Rect frontLayerBound;
private Rect playScreenTitleBound;
private ImageView cardImage1;
private ViewGroup rootLayout;
private int _xDelta;
private int _yDelta;
public View view;
/**
* User input controls for managing the player and the game
*/
// protected InputControl pauseButton
// /////////////////////////////////////////////////////////////////////////
// Constructors
// /////////////////////////////////////////////////////////////////////////
/**
* Create a game
*
* @param game
* Game to which this screen belongs */
public PlayScreen(Game game) {
super("PlayScreen", game);
//Define the rects what will be used to 'hold' the images
int spacingX = game.getScreenWidth() / 8;
int spacingY = game.getScreenHeight() / 8;
int padding = spacingY / 10; //padding between each button
int line = 1; //each button is on a new 'line' (under each other)
// Load in the assets used by the demo
AssetStore assetManager = game.getAssetManager();
assetManager.loadAndAddBitmap("pitch", "img/pitch.png");
assetManager.loadAndAddBitmap("backButton", "img/back_button.png");
assetManager.loadAndAddBitmap("hazardCard", "img/hazard_card.jpg");
// Define Rectangles for Bitmaps
// playScreenTitleBound = new Rect(spacingX * 2, spacingY * 0, spacingX * 6, spacingY * 1);
this.backgroundBitmap = assetManager.getBitmap("pitch");
this.backButton = assetManager.getBitmap("backButton");
this.hazardCard = assetManager.getBitmap("hazardCard");
//load in sounds
assetManager.loadAndAddMusic("screenClickMusic", "music/buttonPress.mp3");
//initialise
this.screenClickMusic = assetManager.getMusic("screenClickMusic");
}
// /////////////////////////////////////////////////////////////////////////
// Support methods
// /////////////////////////////////////////////////////////////////////////
// /////////////////////////////////////////////////////////////////////////
// Update and Draw methods
// /////////////////////////////////////////////////////////////////////////
@Override
public void update(ElapsedTime elapsedTime) {
//process any touch events occurring since the update
Input input = game.getInput();
List<TouchEvent> touchEvents = input.getTouchEvents();
if (touchEvents.size() > 0) {
//Just check the first touch event that occurred in the frame.
//It means pressing the screen with several fingers may not
//trigger a 'button'.
TouchEvent touchEvent = touchEvents.get(0);
if (backButtonBound.contains((int) touchEvent.x, (int) touchEvent.y)
&& touchEvent.type == TouchEvent.TOUCH_UP) {
// If the play game area has been touched then swap screens
game.getScreenManager().removeScreen(this.getName());
MenuScreen menuScreen = new MenuScreen(game);
if (Settings.soundEnabled) {
screenClickMusic.play();
}
// As it's the only added screen it will become active.
game.getScreenManager().addScreen(menuScreen);
} /*else if (hazardCardBound.contains((int) touchEvent.x, (int) touchEvent.y)
&& touchEvent.type == TouchEvent.TOUCH_DOWN) {
RelativeLayout.LayoutParams lparams = (RelativeLayout.LayoutParams) view.getLayoutParams();
_xDelta = X - lparams.leftMargin;
_yDelta = Y - lparams.topMargin;
}*/
}
}
@Override
public void draw(ElapsedTime elapsedTime, IGraphics2D graphics2D) {
// load hazard playing card
/*ImageView hazardCardImageView = (ImageView) view.findViewById(R.id.hazardCardImageView);
if (hazardCard != null) {
hazardCardImageView.setImageBitmap(hazardCard);
}
cardImage1 = (ImageView) rootLayout.findViewById(R.id.hazardCardImageView);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(500, 150);
cardImage1.setLayoutParams(layoutParams);
cardImage1.setOnTouchListener(new ChoiceTouchListener());*/
// Get and draw the bitmaps into the defined rectangles
Bitmap backButton = game.getAssetManager().getBitmap("backButton");
// Create the screen to black and define a clip based on the viewport
graphics2D.clear(Color.BLACK);
//graphics2D.clipRect(mScreenViewport.toRect());
// Define the rects what will be used to 'hold' the images
int spacingX = game.getScreenWidth() / 8;
int spacingY = game.getScreenHeight() / 8;
int padding = spacingY / 10; //padding between each button
int line = 1; //each button is on a new 'line' (under each other)
hazardCardBound = new Rect(spacingX, spacingY * 2 + padding, spacingX * 7, spacingY * 3);
if (frontLayerBound == null) {
frontLayerBound = new Rect(0, 0, graphics2D.getSurfaceWidth(),
graphics2D.getSurfaceHeight());
}
if (backButtonBound == null) {
int left = 10;
int bottom = (graphics2D.getSurfaceHeight() - 120);
backButtonBound = new Rect(left, bottom, left + 100, bottom + 120);
}
//添加了代码 cardImage1 =（ImageView）rootLayout.findViewById（R.id.hazardCardImageView）;
cardImage1.setLayoutParams(layoutParams);
cardImage1.setOnTouchListener(new ChoiceTouchListener());
cardImage1.setOnTouchListener(new ChoiceTouchListener());
cardImage1.setImageBitmap(hazardCard);*/
//draw bitmaps with relative bounds
graphics2D.drawBitmap(backgroundBitmap, null, frontLayerBound,null);
graphics2D.drawBitmap(backButton, null, backButtonBound, null);
graphics2D.drawBitmap(hazardCard,null, hazardCardBound, null);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(500, 150);
cardImage1.setLayoutParams(layoutParams);
cardImage1.setImageBitmap(hazardCard);
cardImage1.setOnTouchListener(new ChoiceTouchListener());
}
private final class ChoiceTouchListener implements View.OnTouchListener {
public boolean onTouch(View view, MotionEvent event) {
final int X = (int) event.getRawX();
final int Y = (int) event.getRawY();
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
RelativeLayout.LayoutParams lparams = (RelativeLayout.LayoutParams) view.getLayoutParams();
_xDelta = X - lparams.leftMargin;
_yDelta = Y - lparams.topMargin;
break;
case MotionEvent.ACTION_UP:
break;
case MotionEvent.ACTION_POINTER_DOWN:
break;
case MotionEvent.ACTION_POINTER_UP:
break;
case MotionEvent.ACTION_MOVE:
RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
layoutParams.leftMargin = X - _xDelta;
layoutParams.topMargin = Y - _yDelta;
layoutParams.rightMargin = 0b11111111111111111111111100000110;
layoutParams.bottomMargin = 0b11111111111111111111111100000110;
view.setLayoutParams(layoutParams);
break;
}
rootLayout.invalidate();
return true;
}
}
编辑注意：我在代码行中添加了初始化imageView ..
编辑：主要活动类：
import android.app.Activity;
import android.app.FragmentManager;
import android.graphics.PointF;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import com.example.llave_000.shootout.world.DemoGame;
import android.view.GestureDetector;
import android.widget.ImageView;
public class MainActivity extends Activity implements View.OnTouchListener {
private float mScaleFactor = 1.0f;
private float mRotationDegrees = 0.f;
private float mFocusX = 0.f;
private float mFocusY = 0.f;
private ImageView cardImage1;
private ViewGroup rootLayout;
/**
* Game fragment instance
*/
private Game mGame;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
cardImage1 = (ImageView) rootLayout.findViewById(R.id.hazardCardImageView);
// Setup Gesture Detectors
mScaleDetector = new ScaleGestureDetector(getApplicationContext(), new ScaleListener());
/*mRotateDetector = new RotationGestureDetector(getApplicationContext(), new RotateListener());
mMoveDetector = new MoveGestureDetector(getApplicationContext(), new MoveListener());*/
// Setup the window as suitable for a game, namely: full screen
// with no title and a request to keep the screen on. The changes
// are made before any content is inflated.
Window window = getWindow();
window.requestFeature(Window.FEATURE_NO_TITLE);
window.addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
// Set the content view to use a simple frame layout
setContentView(R.layout.activity_main);
// Add in the main game fragment..
FragmentManager fm = getFragmentManager();
// MenuScreen menuScreen = (MenuScreen)fm.findFragmentById(R.id.activity_main_id);
mGame = (Game)fm.findFragmentById(R.id.activity_main_id);
if (mGame == null) {
mGame = new DemoGame(); //not sure if correct
fm.beginTransaction().add(R.id.activity_main_id, mGame)
.commit();
}
}
@Override
public void onBackPressed() {
// If the fragment does not consume the back event then
// trigger the default behaviour
if(!mGame.onBackPressed())
super.onBackPressed();
}
/* public boolean onTouchEvent(MotionEvent me) {
if (me.getAction() == MotionEvent.ACTION_DOWN) {
//code in here to take me to new screen with match attax background
//with new screen displaying a card. then work on being able to move that card.
//playButtonY -= 20;
}*/
// playButton.setY(playButtonY);
//code in here to take me to new screen with match attax background
//with new screen displaying a card. then work on being able to move that card.
//return true;
}
新错误：
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.llave_000.shootout/com.example.llave_000.shootout.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
at com.example.llave_000.shootout.MainActivity.onCreate(MainActivity.java:42)
at android.app.Activity.performCreate(Activity.java:6662)
编辑:: GameScreen类：
import com.example.llave_000.shootout.Game;
import com.example.llave_000.shootout.engine.ElapsedTime;
import com.example.llave_000.shootout.engine.graphics.IGraphics2D;
import com.example.llave_000.shootout.util.ILifeCycle;
/**
* GameScreen - represents a type of Screen in the Game.
* methods
*
*/
public abstract class GameScreen {
/**
* Name that is given to this game screen
*/
protected final String name;
/**
* Return the name of this game screen
*
* @return Name of this game screen
*/
public String getName() {
return name;
}
/**
* Game to which game screen belongs
*/
protected final Game game;
/**
* Return the game to which this game screen is attached
*
* @return Game to which screen is attached
*/
public Game getGame() {
return game;
}
/**
* Create a new game screen associated with the specified game instance
*
* @param game
* Game instance to which the game screen belongs
*/
public GameScreen(String name, Game game) {
this.name = name;
this.game = game;
}
/**
* Update the game screen. Invoked automatically from the game.
*
* NOTE: If the update is multi-threaded control should not be returned from
* the update call until all update processes have completed.
*
* @param elapsedTime
* Elapsed time information for the frame
*/
public abstract void update(ElapsedTime elapsedTime);
/**
* Draw the game screen. Invoked automatically from the game.
*
* @param elapsedTime
* Elapsed time information for the frame
* @param graphics2D
* Graphics instance used to draw the screen
*/
public abstract void draw(ElapsedTime elapsedTime, IGraphics2D graphics2D);
/**
* Invoked automatically by the game whenever the app is paused.
*/
public void pause() {
}
/**
* Invoked automatically by the game whenever the app is resumed.
*/
public void resume() {
}
/**
* Invoked automatically by the game whenever the app is disposed.
*/
public void dispose() {
}
}
答案 0 :(得分：0)
您的cardImage1未初始化。您正在null imageview上设置布局参数。这就是它获得NullPointerException的原因。
如果它解决了您的问题，那么它会更好您的问题和错误日志。