Android: Simple bullet screen effect implementation

<span id="Label3"></p><p><p>first, The Harassment Phone page is detected similar to 360:</p></p><p><p><br></p></p><p><p>The layout is simple, above is a relativelayout, the following Button.<br></p></p><p><p>Function:</p></p><p><p>(1) after the barrage is generated, it automatically scrolls from the right to the left (translateanimation) and is removed immediately after the barrage Disappears.</p></p><p><p>(2) the position of the projectile appears randomly and does not repeat (prevents the text from overlapping).</p></p><p><p>(3) the font size is randomly changed within a certain range, and the font color can be set.</p></p><p><p>(4) Custom First deceleration, after the acceleration of the interpolator, the barrage to accelerate the entry, deceleration stay, and then accelerate Out.</p></p><p><p>1.Activity code:</p></p><p><p></p></p><pre name="code" class="java">/** * Simple bullet screen effect implementation * Created by admin on 15-6-4. */public class Mainactivity extends actionbaractivity {private MyHandler handler; The content of the barrage is private Tanmubean tanmubean; The parent component that placed the content of the bullet screen private relativelayout containervg; The height of the parent component, private int validheightspace; @Override protected void onCreate (Bundle Savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (r.layout.activity_main); CONTAINERVG = (relativelayout) Findviewbyid (r.id.tanmu_container); Tanmubean = new Tanmubean (); Tanmubean.setitems (new string[]{"test", "bomb screen This thing really bad do ah", "always come up with various problems ~ ~", "do not know why?" Trouble! "and who is the great God who can help me?" "I need your help.", "test it", "it's A bad thing to do", "always come up with all kinds of problems ~ ~", "do not know why?" Trouble! "and who is the great God who can help me?" "I need your help.", "test it", "it's A bad thing to do", "always come up with all kinds of problems ~ ~", "do not know why?" Trouble! "and who is the great God who can help me?" "," I Need your help. "}); Handler = new MyHandler (this); Start the barrage View Starttanmuview = Findviewbyid (r.id.starttanmu); STarttanmuview.setonclicklistener (new view.onclicklistener () {@Override public void OnClick (View V) {if (containervg.getchildcount () > 0) {return; } existmarginvalues.clear (); New Thread (new createtanmuthread ()). start (); } }); }//2s automatically add a pop-up screen private class Createtanmuthread implements Runnable {@Override public void run () { int N = Tanmubean.getitems (). length; for (int i = 0; i < N; i++) {handler.obtainmessage (1, i, 0). sendtotarget (); Systemclock.sleep (2000); }}}//need to add components in mainline City private static class MyHandler extends Handler {private Weakreference<maina Ctivity> ref; MyHandler (mainactivity Ac) {ref = new Weakreference<> (ac); } @Override public void Handlemessage (Message Msg) {super.handlemEssage (msg); if (msg.what = = 1) {mainactivity ac = ref.get (); If (ac! = null && ac.tanmubean! = null) {int index = msg.arg1; String content = Ac.tanmuBean.getItems () [index]; float textSize = (float) (ac.tanmuBean.getMinTextSize () * (1 + math.random () * Ac.tanmuBean.getRange ())); int textcolor = Ac.tanmuBean.getColor (); Ac.showtanmu (content, textSize, textcolor); }}}} private void Showtanmu (String content, float textSize, int textcolor) {final TEXTV Iew TextView = new TextView (this); Textview.settextsize (textSize); Textview.settext (content);//textview.setsingleline (); Textview.settextcolor (textcolor); int leftMargin = containervg.getright ()-containervg.getleft ()-containervg.getpaddingleft (); Calculates the TopMargin (random value, but not the one already in the screen) of this bullet, int VerticalmaRgin = Getrandomtopmargin (); Textview.settag (verticalmargin); Layoutparams params = new Layoutparams (layoutparams.wrap_content, layoutparams.wrap_content); Params.addrule (relativelayout.align_parent_top); Params.topmargin = verticalmargin; Textview.setlayoutparams (params); Animation anim = Animationhelper.createtranslateanim (this, leftMargin,-screenutils.getscreenw (this)); Anim.setanimationlistener (new animation.animationlistener () {@Override public void Onanimationstart (Animation Animation) {} @Override public void Onanimationend (Animation Animation) {//remove the component Containervg.removeview (textView); Remove the placeholder int verticalmargin = (int) Textview.gettag (); Existmarginvalues.remove (verticalmargin); } @Override public void Onanimationrepeat (Animation Animation) {}}); Textview.startanimation (anim); Containervg.addview (textView); }//record the current position of the barrage that is still showing (avoid duplication) private set<integer> existmarginvalues = new Hashset<> (); private int linescount; private int Getrandomtopmargin () {//calculates The space height to be used for the barrage display if (validheightspace = = 0) {validheightspace = Containervg.getbottom ()-containervg.gettop ()-containervg.getpaddingtop ()-containervg.getpadding Bottom (); }//calculates the number of available rows if (linescount = = 0) {linescount = validheightspace/screenutils.dp2px (this, tanmub Ean.getmintextsize () * (1 + tanmubean.getrange ())); if (linescount = = 0) {throw new runtimeexception ("not enough space to show text."); }}//check overlap While (true) {int Randomindex = (int) (math.random () * linescount); int marginvalue = Randomindex * (validheightspace/linescount); If (!existmarginvalues.contains(marginvalue)) {existmarginvalues.add (marginvalue); Return marginvalue; } } }}</pre>2. Pan the animation generation Tool:<p><p></p></p><p><p></p></p><pre name="code" class="java"><pre name="code" class="java">public class Animationhelper { /** * Creates a translation animation * /public static Animation Createtranslateanim (Context context, int fromX, int toX) { translateanimation tlanim = new translateanimation (fromX, toX, 0, 0); Automatic calculation time long duration = (long) (math.abs (tox-fromx) * 1.0f/screenutils.getscreenw (context) * 4000); Tlanim.setduration (duration); Tlanim.setinterpolator (new decelerateaccelerateinterpolator ()); Tlanim.setfillafter (true); return tlanim;} }</pre></pre>The Screenutils is the tool class used to get the screen width high, the DP and PX.<p><p></p></p><p><p>3. Custom interpolator, in fact, there is only one line of code</p></p><p><p></p></p><pre name="code" class="java"><pre name="code" class="java">The public class Decelerateaccelerateinterpolator implements Interpolator { //input from 0~1, and the return value is also from 0~1. curve characterization of return values speed plus minus trend @Override public float getinterpolation (float input) { return (float) (math.tan (input * 2-1)/4 * Math.PI )/2.0f + 0.5f;} }</pre></pre>4.TanmuBean is an entity class<p><p></p></p><p><p></p></p><pre name="code" class="java"><pre name="code" class="java">public class Tanmubean { private string[] items; private int color; private int mintextsize; Private float range; Public Tanmubean () { //init default value color = Color.parsecolor ("#eeeeee"); Mintextsize = +; Range = 0.5f; } Public string[] getItems () { return items; } public void Setitems (string[] items) { this.items = items; } public int GetColor () { return color; } public void SetColor (int color) { this.color = color; } /** * min textSize, in dp. * /public int getmintextsize () { return mintextsize; } public void Setmintextsize (int mintextsize) { this.mintextsize = mintextsize; } Public float GetRange () { return range; } public void SetRange (float range) { this.range = range; }}</pre></pre><br><br><br><br><br><p><p></p></p><p><p><br></p></p><p><p><br></p></p><p><p>Android: Simple bullet screen effect implementation</p></p></span>