Android Interface Optimization Tips

<span id="Label3"></p><span style="background-color:inherit"><span style="background-color:inherit">optimization will be discussed in the following aspects</span></span> <ol> <ol> <li><span style="widows:auto; background-color:inherit">How to use Adapter</span></li> <li><span style="widows:auto; background-color:inherit">Backgrounds and images</span></li> <li><span style="widows:auto; background-color:inherit">Update request</span></li> <li><span style="widows:auto; background-color:inherit">views and layouts</span></li> <li><span style="widows:auto; background-color:inherit">Memory allocation</span></li> </ol> </ol><span style="color:rgb(255,0,0); background-color:inherit"><span style="color:rgb(255,0,0); background-color:inherit">adapter:</span></span>The simplest method, the slowest and least practical, updates the frequency of frames per second around 10 using Convertview recycle view, efficiency increase 200%, Update frequency per second frame Number 30 use Viewholder mode, efficiency increase 250%, Update frequency per second transmission Frame number 40 or so<span style="color:#ff0000; background-color:inherit"><span style="color:#ff0000; background-color:inherit"><span style="background-color:inherit">Backgrounds and Images:</span></span></span>Select the appropriate image size, The view background image will always fill the entire view Area: * Image size is not appropriate to cause automatic scaling * Avoid real-time scaling * preferably pre-scaled to the view size Originalim Age = Bitmap.createscaledbitmap (<span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">originalimage,//scaled Image</span></span>View.getwidth (),//view width view.getheight (),//view height true); Dual linear filter background and image update frequency, pre-scaled transmission frames per second around 50, auto-scaling about 25<span style="background-color:inherit"><span style="background-color:inherit"><span style="color:#ff0000; background-color:inherit">window Background:</span></span></span>* By default, The window has an opaque background * can sometimes not be needed.<span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"> </span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-the view at the top level is opaque</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-top-level View covers the entire window fill_parent</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">* Updating unseen backgrounds is a waste of time</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">* Delete window background</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-getWindow (). setbackgrounddrawable (null);</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-<item name= "android:windowbackground" > @null </item></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">window background Update frequency, the background of the number of frames per second in about 42, no background around 50 <span style="background-color:inherit"></span> </span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"> <span style="color:#ff0000; background-color:inherit">update request:</span> </span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">* When the screen needs to be updated, call invalidate ()</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-simple and convenient</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-but will update the entire view, too expensive</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">* It is best to find the invalid zone first and then Call. A more efficient way to do this is to update only the areas that need to be updated</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-invalidate (Rect dirty);</span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5">-invalidate (int left, int top, int. right, int</span></span><span style="line-height:1.5"><span style="line-height:1.5">bottom);</span></span>Window background<span style="background-color:inherit"><span style="background-color:inherit"> </span></span>Update frequency: invalidate transmission about 18 per second, and the last two around 48<span style="color:#ff0000; background-color:inherit"><span style="color:#ff0000; background-color:inherit">views and Layouts:</span></span>* If a window contains many Views-start time long measurement time long layout time long drawing time * If the view tree depth too deep-stackoverflowe Xception user Interface Slow response * Workaround-use TextView's composite drawables to reduce hierarchy-use viewstu b deferred expand view-use <merge> Merge Intermediate view-use relativelayout to reduce levels-use self- Defining views, using custom layouts<span style="background-color:inherit"><span style="background-color:inherit"><span style="color: #ff0000; background-color:inherit">   Memory allocation: </span></span></span>* Do not create Java objects, try to avoid creating Java objects in Performance-sensitive code-measurement: onmeasure ()-layout: onlayout ()                    -drawing: dispatchdraw (), onDraw ()-event handling: dispatchtouchevent (), ontouchevent () -adapter:getview (), BindView () * GC, garbage collection: The entire program will pause, slow (about hundreds of milliseconds * manage good objects * make Best choice of memory cache with soft references * Use weak references to avoid memory leaks<br style="background-color:inherit"> <span style="color:#ff0000; background-color:inherit"><span style="color:#ff0000; background-color:inherit"><span style="background-color:inherit">summary:</span></span></span>* Use Viewholder to achieve Adapter GetView * To select the right image for the background * Update requests for invalid areas * View and layout, the simpler the better * avoid creating on a performance-sensitive path Building objects<span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"><br style="background-color:inherit"></span></span><span style="background-color:inherit; line-height:1.5"><span style="background-color:inherit; line-height:1.5"> </span></span><p><p>Android Interface Optimization Tips</p></p></span>