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首先让我道歉，这是一段很长的帖子，里面有一段代码，但我想要彻底。Android requestFeature（）必须被调用，而不是Dialog
当我点击按钮在我的程序中启动此fragment时，出现logcat错误。这是说明我必须“requestFeature（）之前添加内容”。我已经耗尽了这些论坛上的所有资源。我浏览了关于这个主题的所有16篇文章，但这里有一些只是为了向你展示。
error: requestFeature() must be called before adding content - Still won't work
Dialog problem: requestFeature() must be called before adding content
这些解决方案的工作
的反复出现的主题与这些职位似乎是dialogs一个问题，custom，action等。尝试启动捕获签名的fragment时发生我的错误。相似但不相同。
所以这里是我的代码和我的logcat。
片段
public class CaptureSignature extends Fragment {
private static final Context Context = null;
View view;
LinearLayout mContent;
signature mSignature;
Button mClear, mGetSign, mCancel;
public static String tempDir;
public int count = 1;
public String current = null;
View mView;
File mypath;
private String uniqueId;
private EditText yourName;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
this.getActivity().requestWindowFeature(Window.FEATURE_NO_TITLE);
view = inflater.inflate(R.layout.fragment_signature, container, false);
mClear = (Button) view.findViewById(R.id.clear);
mGetSign = (Button) view.findViewById(R.id.getsign);
mGetSign.setEnabled(false);
mCancel = (Button) view.findViewById(R.id.cancel);
yourName = (EditText) view.findViewById(R.id.yourName);
uniqueId = getTodaysDate() + "_" + getCurrentTime() + "_"
+ Math.random();
current = uniqueId + ".png";
mContent = (LinearLayout) view.findViewById(R.id.linearLayout);
mSignature = new signature(Context, null);
mSignature.setBackgroundColor(Color.WHITE);
mContent.addView(mSignature, LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
mView = mContent;
mClear.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Log.v("log_tag", "Panel Cleared");
mSignature.clear();
mGetSign.setEnabled(false);
}
});
mGetSign.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Log.v("log_tag", "Panel Saved");
boolean error = captureSignature();
if (!error) {
mView.setDrawingCacheEnabled(true);
}
}
});
mCancel.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Log.v("log_tag", "Panel Canceled");
}
});
return view;
}
@Override
public void onDestroy() {
Log.w("GetSignature", "onDestory");
super.onDestroy();
}
private boolean captureSignature() {
boolean error = false;
String errorMessage = "";
if (yourName.getText().toString().equalsIgnoreCase("")) {
errorMessage = errorMessage + "Please enter your Name\n";
error = true;
}
if (error) {
Toast toast = Toast
.makeText(Context, errorMessage, Toast.LENGTH_SHORT);
toast.setGravity(Gravity.TOP, 105, 50);
toast.show();
}
return error;
}
private String getTodaysDate() {
final Calendar c = Calendar.getInstance();
int todaysDate = (c.get(Calendar.YEAR) * 10000)
+ ((c.get(Calendar.MONTH) + 1) * 100)
+ (c.get(Calendar.DAY_OF_MONTH));
Log.w("DATE:", String.valueOf(todaysDate));
return (String.valueOf(todaysDate));
}
private String getCurrentTime() {
final Calendar c = Calendar.getInstance();
int currentTime = (c.get(Calendar.HOUR_OF_DAY) * 10000)
+ (c.get(Calendar.MINUTE) * 100) + (c.get(Calendar.SECOND));
Log.w("TIME:", String.valueOf(currentTime));
return (String.valueOf(currentTime));
}
public class signature extends View {
private static final float STROKE_WIDTH = 5f;
private static final float HALF_STROKE_WIDTH = STROKE_WIDTH/2;
private Paint paint = new Paint();
private Path path = new Path();
private float lastTouchX;
private float lastTouchY;
private final RectF dirtyRect = new RectF();
public signature(Context captureSignature, AttributeSet attrs) {
super(captureSignature, attrs);
paint.setAntiAlias(true);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(STROKE_WIDTH);
}
public void clear() {
path.reset();
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawPath(path, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
mGetSign.setEnabled(true);
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
lastTouchX = eventX;
lastTouchY = eventY;
return true;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
resetDirtyRect(eventX, eventY);
int historySize = event.getHistorySize();
for (int i = 0; i < historySize; i++) {
float historicalX = event.getHistoricalX(i);
float historicalY = event.getHistoricalY(i);
expandDirtyRect(historicalX, historicalY);
path.lineTo(historicalX, historicalY);
}
path.lineTo(eventX, eventY);
break;
default:
debug("Ignored touch event: " + event.toString());
return false;
}
invalidate((int) (dirtyRect.left - HALF_STROKE_WIDTH),
(int) (dirtyRect.top - HALF_STROKE_WIDTH),
(int) (dirtyRect.right + HALF_STROKE_WIDTH),
(int) (dirtyRect.bottom + HALF_STROKE_WIDTH));
lastTouchX = eventX;
lastTouchY = eventY;
return true;
}
private void debug(String string) {
}
private void expandDirtyRect(float historicalX, float historicalY) {
if (historicalX < dirtyRect.left) {
dirtyRect.left = historicalX;
} else if (historicalX > dirtyRect.right) {
dirtyRect.right = historicalX;
}
if (historicalY < dirtyRect.top) {
dirtyRect.top = historicalY;
} else if (historicalY > dirtyRect.bottom) {
dirtyRect.bottom = historicalY;
}
}
private void resetDirtyRect(float eventX, float eventY) {
dirtyRect.left = Math.min(lastTouchX, eventX);
dirtyRect.right = Math.max(lastTouchX, eventX);
dirtyRect.top = Math.min(lastTouchY, eventY);
dirtyRect.bottom = Math.max(lastTouchY, eventY);
}
}
}
主要活动代码
public class Main extends Activity {
TabListener<Store_Fragment> surveyTabListener;
TabListener<Store_Fragment> assetTabListener;
TabListener<Store_Fragment> installTabListener;
TabListener<Store_Fragment> punchTabListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
// instantiate ActionBar
ActionBar actionBar = getActionBar();
//actionBar.setBackgroundDrawable((getResources()
//.getDrawable(R.drawable.titlebarheader)));
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.setTitle("Trakflex");
actionBar.setDisplayShowTitleEnabled(true);
// set surveyTab
Tab surveyTab = actionBar.newTab();
surveyTabListener = new TabListener<Store_Fragment>(this,
R.id.header_fragment_container, Store_Fragment.class);
surveyTab.setText("Survey").setContentDescription("Survey Tab")
.setTabListener(surveyTabListener);
actionBar.addTab(surveyTab);
// set assetTab
Tab assetTab = actionBar.newTab();
assetTabListener = new TabListener<Store_Fragment>(this,
R.id.header_fragment_container, Store_Fragment.class);
assetTab.setText("Assets").setContentDescription("Assets Tab")
.setTabListener(assetTabListener);
actionBar.addTab(assetTab);
// set installTab
Tab installTab = actionBar.newTab();
installTabListener = new TabListener<Store_Fragment>(this,
R.id.header_fragment_container, Store_Fragment.class);
installTab.setText("Install Checklist")
.setContentDescription("Install Checklist Tab")
.setTabListener(installTabListener);
actionBar.addTab(installTab);
// set punchTab
Tab punchTab = actionBar.newTab();
punchTabListener = new TabListener<Store_Fragment>(this,
R.id.header_fragment_container, Store_Fragment.class);
punchTab.setText("Punchlist").setContentDescription("Punchlist Tab")
.setTabListener(punchTabListener);
actionBar.addTab(punchTab);
}
新的logcat
05-13 18:57:19.767: E/AndroidRuntime(8950): FATAL EXCEPTION: main
05-13 18:57:19.767: E/AndroidRuntime(8950): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.facilitysolutionsinc.trackflex/com.facilitysolutionsinc.trackflex.Main}: java.lang.NullPointerException
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.ActivityThread.access$600(ActivityThread.java:141)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.os.Handler.dispatchMessage(Handler.java:99)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.os.Looper.loop(Looper.java:137)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.ActivityThread.main(ActivityThread.java:5041)
05-13 18:57:19.767: E/AndroidRuntime(8950): at java.lang.reflect.Method.invokeNative(Native Method)
05-13 18:57:19.767: E/AndroidRuntime(8950): at java.lang.reflect.Method.invoke(Method.java:511)
05-13 18:57:19.767: E/AndroidRuntime(8950): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
05-13 18:57:19.767: E/AndroidRuntime(8950): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
05-13 18:57:19.767: E/AndroidRuntime(8950): at dalvik.system.NativeStart.main(Native Method)
05-13 18:57:19.767: E/AndroidRuntime(8950): Caused by: java.lang.NullPointerException
05-13 18:57:19.767: E/AndroidRuntime(8950): at com.facilitysolutionsinc.trackflex.Main.onCreate(Main.java:32)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.Activity.performCreate(Activity.java:5104)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
05-13 18:57:19.767: E/AndroidRuntime(8950): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
05-13 18:57:19.767: E/AndroidRuntime(8950): ... 11 more
如果有人Ç一个帮助，我会非常感谢
谢谢@CommonsWare，我知道我可以相信你对这个问题有很好的理解。那么我应该问一下，何时/应该在哪里调用requestWindowFeature（）？在我的主要活动/ ParentActivity？ – IrishWhiskey 2013-05-13 22:42:15
@IrishWhiskey：“何时/应该在哪里调用requestWindowFeature（）？” - 作为'Activity'的'onCreate（）'中的第一个语句。我甚至在'super.onCreate（）'之前看到过它的调用，特别是如果超类自身通过处理内容视图（例如'ListActivity'）。 – CommonsWare 2013-05-13 22:43:26
嗯，我试图把它放在我的'活动'中。在'super'之后，'view'之前的'super'被夸大之前。他们都从现在开始就让我的程序崩溃。我现在有一个'NullPointerException'错误。 **叹**。我已经厌倦了这个问题，而且我完全不了解 – IrishWhiskey 2013-05-13 22:50:12