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我有一個主頁面有兩個按鈕「設置」和「任務」，它打開不同的活動。當我直接進入「任務」活動時，它總是強制關閉，但如果我先進入「設置」，然後返回到主菜單並按下「任務」，它就可以正常工作。我在想，這可能會發生，因爲我在「設置」活動中有一些變量，所以必須在我進入「任務」之前啓動它們。 特別是它是寫在logcat中的錯誤是在XML文件中的第6行，它看起來像這樣：去其他活動時出錯
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<com.example.splasher.ScrollTextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical"
android:id="@+id/scrolltext">
</com.example.splasher.ScrollTextView>
</LinearLayout>
錯誤是：致命的異常：主要的。無法啓動活動componentinfo（com.example.splasher/com.example.splasher.Views）：android.view.InflateException：二進制XML行＃7：錯誤膨脹類com.example.splasher.ScrollTextView ScrollTextView.java的代碼是：
package com.example.splasher;
import android.content.Context;
import android.graphics.Rect;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.view.animation.LinearInterpolator;
import android.widget.Scroller;
import android.widget.TextView;
public class ScrollTextView extends TextView {
// scrolling feature
private Scroller mSlr;
// milliseconds for a round of scrolling
private int mRndDuration = Integer.parseInt(Settings.speed[Settings.Speed.getSelectedItemPosition()]);
// the X offset when paused
private int mXPaused = 0;
// whether it's being paused
private boolean mPaused = true;
/*
* constructor
*/
public ScrollTextView(Context context) {
this(context, null);
// customize the TextView
setSingleLine();
setEllipsize(null);
setVisibility(INVISIBLE);
}
/*
* constructor
*/
public ScrollTextView(Context context, AttributeSet attrs) {
this(context, attrs, android.R.attr.textViewStyle);
// customize the TextView
setSingleLine();
setEllipsize(null);
setVisibility(INVISIBLE);
}
/*
* constructor
*/
public ScrollTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// customize the TextView
setSingleLine();
setEllipsize(null);
setVisibility(INVISIBLE);
}
/**
* begin to scroll the text from the original position
*/
public void startScroll() {
// begin from the very right side
mXPaused = -1 * getWidth();
// assume it's paused
mPaused = true;
resumeScroll();
}
/**
* resume the scroll from the pausing point
*/
public void resumeScroll() {
if (!mPaused)
return;
// Do not know why it would not scroll sometimes
// if setHorizontallyScrolling is called in constructor.
setHorizontallyScrolling(true);
// use LinearInterpolator for steady scrolling
mSlr = new Scroller(this.getContext(), new LinearInterpolator());
setScroller(mSlr);
int scrollingLen = calculateScrollingLen();
int distance = scrollingLen - (getWidth() + mXPaused);
int duration = (new Double(mRndDuration * distance * 1.00000
/scrollingLen)).intValue();
setVisibility(VISIBLE);
mSlr.startScroll(mXPaused, 0, distance, 0, duration);
mPaused = false;
}
/**
* calculate the scrolling length of the text in pixel
*
* @return the scrolling length in pixels
*/
private int calculateScrollingLen() {
TextPaint tp = getPaint();
Rect rect = new Rect();
String strTxt = getText().toString();
tp.getTextBounds(strTxt, 0, strTxt.length(), rect);
int scrollingLen = rect.width() + getWidth();
rect = null;
return scrollingLen;
}
/**
* pause scrolling the text
*/
public void pauseScroll() {
if (null == mSlr)
return;
if (mPaused)
return;
mPaused = true;
// abortAnimation sets the current X to be the final X,
// and sets isFinished to be true
// so current position shall be saved
mXPaused = mSlr.getCurrX();
mSlr.abortAnimation();
}
@Override
/*
* override the computeScroll to restart scrolling when finished so as that
* the text is scrolled forever
*/
public void computeScroll() {
super.computeScroll();
if (null == mSlr) return;
if (mSlr.isFinished() && (!mPaused)) {
this.startScroll();
}
}
public int getRndDuration() {
return mRndDuration;
}
public void setRndDuration(int duration) {
this.mRndDuration = duration;
}
public boolean isPaused() {
return mPaused;
}
}
任何想法發生了什麼問題？ 全logcatt：
03-18 00:04:26.161: E/AndroidRuntime(24081): FATAL EXCEPTION: main
03-18 00:04:26.161: E/AndroidRuntime(24081): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.splasher/com.example.splasher.Views}: android.view.InflateException: Binary XML file line #7: Error inflating class com.example.splasher.ScrollTextView
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.ActivityThread.access$1500(ActivityThread.java:135)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.os.Handler.dispatchMessage(Handler.java:99)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.os.Looper.loop(Looper.java:150)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.ActivityThread.main(ActivityThread.java:4385)
03-18 00:04:26.161: E/AndroidRuntime(24081): at java.lang.reflect.Method.invokeNative(Native Method)
03-18 00:04:26.161: E/AndroidRuntime(24081): at java.lang.reflect.Method.invoke(Method.java:507)
03-18 00:04:26.161: E/AndroidRuntime(24081): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
03-18 00:04:26.161: E/AndroidRuntime(24081): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
03-18 00:04:26.161: E/AndroidRuntime(24081): at dalvik.system.NativeStart.main(Native Method)
03-18 00:04:26.161: E/AndroidRuntime(24081): Caused by: android.view.InflateException: Binary XML file line #7: Error inflating class com.example.splasher.ScrollTextView
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.createView(LayoutInflater.java:518)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:570)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.rInflate(LayoutInflater.java:623)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.inflate(LayoutInflater.java:408)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
03-18 00:04:26.161: E/AndroidRuntime(24081): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:250)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.Activity.setContentView(Activity.java:1742)
03-18 00:04:26.161: E/AndroidRuntime(24081): at com.example.splasher.Views.onCreate(Views.java:26)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
03-18 00:04:26.161: E/AndroidRuntime(24081): ... 11 more
03-18 00:04:26.161: E/AndroidRuntime(24081): Caused by: java.lang.reflect.InvocationTargetException
03-18 00:04:26.161: E/AndroidRuntime(24081): at java.lang.reflect.Constructor.constructNative(Native Method)
03-18 00:04:26.161: E/AndroidRuntime(24081): at java.lang.reflect.Constructor.newInstance(Constructor.java:415)
03-18 00:04:26.161: E/AndroidRuntime(24081): at android.view.LayoutInflater.createView(LayoutInflater.java:505)
03-18 00:04:26.161: E/AndroidRuntime(24081): ... 21 more
03-18 00:04:26.161: E/AndroidRuntime(24081): Caused by: java.lang.NullPointerException
03-18 00:04:26.161: E/AndroidRuntime(24081): at com.example.splasher.ScrollTextView.<init>(ScrollTextView.java:17)
03-18 00:04:26.161: E/AndroidRuntime(24081): at com.example.splasher.ScrollTextView.<init>(ScrollTextView.java:40)
03-18 00:04:26.161: E/AndroidRuntime(24081): ... 24 more
後的*整個堆棧跟蹤* – 2013-03-18 00:18:47
我更新了我的問題 – 2013-03-18 00:24:03
檢查03-18 00：04：26.161：NPE在com.example.splasher.ScrollTextView。（ScrollTextView.java:17） –
2013-03-18 00:25:57