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AndroidT/gist:b52eb22778da5317b969

Last active November 20, 2015 02:29
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viewpager的小动画
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gistfile1.txt
package cn.iwgang.parallaxguidedemo;
import android.annotation.SuppressLint;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
/**
Android 视差引导页面
github:https://github.com/iwgang/ParallaxGuideDemo
*/
public class MainActivity extends ActionBarActivity {
private ViewPager mViewPager;
private Button mBtnGo;
private ViewPaperAdapter vpAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
}
private void initViews() {
mViewPager = (ViewPager)findViewById(R.id.vp_guide);
mBtnGo = (Button)findViewById(R.id.btn_go);
//实例化各个界面的布局对象
View view1 = View.inflate(this, R.layout.guide_view, null);
View view2 = View.inflate(this, R.layout.guide_view, null);
View view3 = View.inflate(this, R.layout.guide_view, null);
((ImageView)view1.findViewById(R.id.tv_pic)).setImageResource(R.drawable.android_guide_step_1);
((ImageView)view2.findViewById(R.id.tv_pic)).setImageResource(R.drawable.android_guide_step_2);
((ImageView)view3.findViewById(R.id.tv_pic)).setImageResource(R.drawable.android_guide_step_3);
mBtnGo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "Go Home", Toast.LENGTH_SHORT).show();
}
});
view1.findViewById(R.id.tv_pic).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mViewPager.setCurrentItem(0);
}
});
view2.findViewById(R.id.tv_pic).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mViewPager.setCurrentItem(1);
}
});
view3.findViewById(R.id.tv_pic).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mViewPager.setCurrentItem(2);
}
});
((TextView)view1.findViewById(R.id.tv_title)).setText("精彩首页");
((TextView)view1.findViewById(R.id.tv_title)).setTextColor(Color.parseColor("#FF5000"));
((TextView)view2.findViewById(R.id.tv_title)).setText("发现定位");
((TextView)view2.findViewById(R.id.tv_title)).setTextColor(Color.parseColor("#49ca65"));
((TextView)view3.findViewById(R.id.tv_title)).setText("欢乐互动");
((TextView)view3.findViewById(R.id.tv_title)).setTextColor(Color.parseColor("#16c5c6"));
((TextView)view1.findViewById(R.id.tv_desc)).setText("优惠第一时间为你奉上\n");
((TextView)view2.findViewById(R.id.tv_desc)).setText("给你最好的\n做你最想要的");
((TextView)view3.findViewById(R.id.tv_desc)).setText("欢迎互动\n精彩由你");
mViewPager = (ViewPager) findViewById(R.id.vp_guide);
ArrayList<View> views = new ArrayList<>();
views.add(view1);
views.add(view2);
views.add(view3);
vpAdapter = new ViewPaperAdapter(views);
mViewPager.setOffscreenPageLimit(views.size());
mViewPager.setPageMargin(-dip2px(135));
mViewPager.setAdapter(vpAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
if (position + 1 == mViewPager.getAdapter().getCount()) {
if (mBtnGo.getVisibility() != View.VISIBLE) {
mBtnGo.setVisibility(View.VISIBLE);
mBtnGo.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, android.R.anim.fade_in));
}
} else {
if (mBtnGo.getVisibility() != View.GONE) {
mBtnGo.setVisibility(View.GONE);
mBtnGo.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, android.R.anim.fade_out));
}
}
}
});
mViewPager.setPageTransformer(false, new ViewPager.PageTransformer() {
private static final float MIN_SCALE = 0.85f;
// private static final float MIN_ALPHA = 0.5f;
private static final float MIN_TXT_SCALE = 0.0f;
private static final float MIN_TXT_ALPHA = 0.0f;
@SuppressLint("NewApi")
@Override
public void transformPage(View view, float position) {
View mGuideImage = view.findViewById(R.id.tv_pic);
View mTitle = view.findViewById(R.id.tv_title);
View mDesc = view.findViewById(R.id.tv_desc);
int viewWidth = mDesc.getWidth();
if (position < -1) {
mTitle.setAlpha(0);
mDesc.setAlpha(0);
} else if (position <= 1) {
float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
float scaleTxtFactor = Math.max(MIN_TXT_SCALE, 1 - Math.abs(position));
// float horzMargin = viewWidth * (1 - (1 - Math.abs(position))) / 2;
// if (position < 0) {
// mTitle.setTranslationX(horzMargin);
// mDesc.setTranslationX(horzMargin);
// } else {
// mTitle.setTranslationX(-horzMargin);
// mDesc.setTranslationX(-horzMargin);
// }
mGuideImage.setScaleX(scaleFactor);
mGuideImage.setScaleY(scaleFactor);
mTitle.setScaleX(scaleTxtFactor);
mTitle.setScaleY(scaleTxtFactor);
mTitle.setAlpha(MIN_TXT_ALPHA + (scaleTxtFactor - MIN_TXT_SCALE) / (1 - MIN_TXT_SCALE) * (1 - MIN_TXT_ALPHA));
mDesc.setAlpha(mTitle.getAlpha());
mDesc.setScaleX(scaleTxtFactor);
mDesc.setScaleY(scaleTxtFactor);
} else {
mTitle.setAlpha(0);
mDesc.setAlpha(0);
}
}
});
}
private int dip2px(float dpValue) {
final float scale = getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
}
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