java - 如何在android studio中修复java中的java运行时异常?
问题描述
这一定是一个简单的问题,我不明白如何解决。我正在制作一个程序,该程序通过使用单元格(正方形)并随机洗牌来随机生成迷宫。当我尝试运行代码时它崩溃并在 logcat 中给了我这个:
2020-05-05 01:34:14.798 5891-5891/com.example.maze E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.maze, PID: 5891
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.maze/com.example.maze.MainActivity}: android.view.InflateException: Binary XML file line #19 in com.example.maze:layout/activity_main: Binary XML file line #19 in com.example.maze:layout/activity_main: Error inflating class com.example.maze.GameView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3333)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3477)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2043)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:216)
at android.app.ActivityThread.main(ActivityThread.java:7464)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:549)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:955)
Caused by: android.view.InflateException: Binary XML file line #19 in com.example.maze:layout/activity_main: Binary XML file line #19 in com.example.maze:layout/activity_main: Error inflating class com.example.maze.GameView
Caused by: android.view.InflateException: Binary XML file line #19 in com.example.maze:layout/activity_main: Error inflating class com.example.maze.GameView
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
at android.view.LayoutInflater.createView(LayoutInflater.java:852)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:1004)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1121)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
at android.view.LayoutInflater.inflate(LayoutInflater.java:680)
at android.view.LayoutInflater.inflate(LayoutInflater.java:532)
at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:555)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:161)
at com.example.maze.MainActivity.onCreate(MainActivity.java:12)
at android.app.Activity.performCreate(Activity.java:7990)
at android.app.Activity.performCreate(Activity.java:7979)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3308)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3477)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2043)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:216)
at android.app.ActivityThread.main(ActivityThread.java:7464)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:549)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:955)
Caused by: java.lang.OutOfMemoryError: Failed to allocate a 167772176 byte allocation with 8388608 free bytes and 110MB until OOM, target footprint 93743400, growth limit 201326592
at java.util.Arrays.copyOf(Arrays.java:3136)
at java.util.Arrays.copyOf(Arrays.java:3106)
2020-05-05 01:34:14.799 5891-5891/com.example.maze E/AndroidRuntime: at java.util.Vector.grow(Vector.java:266)
at java.util.Vector.ensureCapacityHelper(Vector.java:246)
at java.util.Vector.addElement(Vector.java:620)
at java.util.Stack.push(Stack.java:67)
at com.example.maze.GameView.createMaze(GameView.java:108)
at com.example.maze.GameView.<init>(GameView.java:34)
... 28 more
下面是我的程序。我认为问题出在 stack.push(current) 代码行(java 108)。该程序不在主要活动类中。创建项目时,我没有触及主要的活动类。这是在它自己的名为 GameView 的类中。
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import androidx.annotation.Nullable;
import java.util.ArrayList;
import java.util.Random;
import java.util.Stack;
public class GameView extends View {
private Cell[][] cells;
private static final int COLS = 14, ROWS = 5;
private static final float WALL_THICKNESS = 4;
private float cellSize, hMargin, vMargin;
private Paint wallPaint;
private Random random;
public GameView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
wallPaint = new Paint();
wallPaint.setColor(Color.BLACK);
wallPaint.setStrokeWidth(WALL_THICKNESS);
random = new Random();
createMaze();
}
private Cell getNeighbor(Cell cell) {
ArrayList<Cell> neighbors = new ArrayList<>();
//left neighbor
if(cell.col > 0)
if(!cells[cell.col-1][cell.row].visited)
neighbors.add(cells[cell.col-1][cell.row]);
//right neighbor
if(cell.col < COLS-1)
if(!cells[cell.col+1][cell.row].visited)
neighbors.add(cells[cell.col+1][cell.row]);
//top neighbor
if(cell.row > 0)
if(!cells[cell.col][cell.row-1].visited)
neighbors.add(cells[cell.col][cell.row-1]);
//bottom neighbor
if(cell.row < ROWS-1)
if(!cells[cell.col][cell.row+1].visited)
neighbors.add(cells[cell.col][cell.row+1]);
if(neighbors.size() > 0) {
int index = random.nextInt(neighbors.size());
return neighbors.get(index);
}
return null;
}
private void removeWall(Cell current, Cell next) {
if(current.col == next.col && current.row == next.row+1) {
current.topWall = false;
next.bottomWall = false;
}
if(current.col == next.col && current.row == next.row-1) {
current.bottomWall = false;
next.topWall = false;
}
if(current.col == next.col+1 && current.row == next.row) {
current.leftWall = false;
next.rightWall = false;
}
if(current.col == next.col-1 && current.row == next.row) {
current.rightWall = false;
next.leftWall = false;
}
}
private void createMaze() {
Stack<Cell> stack = new Stack<>();
Cell current, next;
cells = new Cell[COLS][ROWS];
for(int x = 0; x < COLS; x++) {
for(int y = 0; y < ROWS; y++) {
cells[x][y] = new Cell(x, y);
}
}
current = cells[0][0];
current.visited = true;
next = getNeighbor(current);
do {
if(next != null) {
removeWall(current, next);
stack.push(current);
current = next;
current.visited = true;
} else
current = stack.pop();
} while(!stack.empty());
}
@Override
protected void onDraw(Canvas canvas) {
//super.onDraw(canvas);
canvas.drawColor(Color.GREEN);
int width = getWidth();
int height = getHeight();
if(width/height < COLS/ROWS)
cellSize = width/(COLS+1);
else
cellSize = height/(ROWS+1);
hMargin = (width - COLS * cellSize)/2;
vMargin = (height-ROWS * cellSize)/2;
canvas.translate(hMargin, vMargin);
for(int x = 0; x < COLS; x++) {
for(int y = 0; y < ROWS; y++) {
if(cells[x][y].topWall)
canvas.drawLine(
x * cellSize,
y * cellSize,
(x+1) * cellSize,
y * cellSize,
wallPaint);
if(cells[x][y].leftWall)
canvas.drawLine(
x * cellSize,
y * cellSize,
x * cellSize,
(y+1) * cellSize,
wallPaint);
if(cells[x][y].bottomWall)
canvas.drawLine(
x * cellSize,
(y+1) * cellSize,
(x+1) * cellSize,
(y+1) * cellSize,
wallPaint);
if(cells[x][y].rightWall)
canvas.drawLine(
(x+1) * cellSize,
y * cellSize,
(x+1) * cellSize,
(y+1) * cellSize,
wallPaint);
}
}
}
private class Cell {
boolean
topWall = true,
leftWall = true,
bottomWall = true,
rightWall = true,
visited = false;
int col, row;
public Cell(int col, int row) {
this.col = col;
this.row = row;
}
}
}
解决方案
这是堆栈跟踪的相关部分:
Caused by: java.lang.OutOfMemoryError: Failed to allocate a 167772176 byte allocation with 8388608 free bytes and 110MB until OOM, target footprint 93743400, growth limit 201326592
at java.util.Arrays.copyOf(Arrays.java:3136)
at java.util.Arrays.copyOf(Arrays.java:3106)
at java.util.Vector.grow(Vector.java:266)
at java.util.Vector.ensureCapacityHelper(Vector.java:246)
at java.util.Vector.addElement(Vector.java:620)
at java.util.Stack.push(Stack.java:67)
at com.example.maze.GameView.createMaze(GameView.java:108)
at com.example.maze.GameView.<init>(GameView.java:34)
那么堆栈跟踪说明了什么?
它说应用程序正在尝试分配一个 167Mbyte 数组 (!!),但由于堆已满而失败。
它说分配发生在尝试创建数组的副本时
它说这个数组复制发生在它扩展一个
Vector
它说
Vector
扩展发生在将元素推到Stack
.它表示
Stack
正在您的createMaze
方法中调用推送。
简而言之,您的createMaze
方法已经创建了一个Stack
目前有数百万个元素深的......到目前为止。
问题出在这个循环中:
do {
if (next != null) {
removeWall(current, next);
stack.push(current);
current = next;
current.visited = true;
} else
current = stack.pop();
} while(!stack.empty());
如果next
不是null
,你“推”,否则你“弹出”。但是你在哪里改变 next
循环?
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