Android项目欢迎界面实现方式及代码

效果如图：

MyCircleView代码：

package com.example.mytest;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class MyCircleView extends View{

	//radius 圆球半径
	private static final float radius = 5.0f;
	private int count;
	private int choose=0;
	//圆球之间的间距
	private int gap = 20;
	public MyCircleView(Context context, AttributeSet attrs) {
		super(context, attrs);
	}
	public void choose(int pos){
		this.choose = pos;
		
		//每次选择的时候重画
		this.invalidate();
	}
	public void setCount(int cnt){
		this.count = cnt;
		
	}
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		
		Paint mPaint = new Paint();
		//设置圆球的锯齿
		mPaint.setAntiAlias(true);
		int width = getWidth();
		int height = getHeight();
		//设置圆球从居中位置开始布置
		int start_x = (width-gap*(count-1))/2;
		for(int i=0;i

WelcomeActivity代码：

package com.example.mytest;

import com.example.constants.Constants;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.Button;
import android.widget.ImageView;

public class WelcomeActivity extends FragmentActivity {

	private MyCircleView circle;
	private Activity activity = this;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.welcome_main);

		SharedPreferences mSharedPreferences = getSharedPreferences(Constants.FILE_NAME, MODE_PRIVATE);
		boolean temp = mSharedPreferences.getBoolean(Constants.ISFIRSTRUN_KEY, true);

		// 表示第一次启动
//		if (temp) {
//			mSharedPreferences.edit().putBoolean(Constants.ISFIRSTRUN_KEY, false).commit();
//
//		} else {
//			Intent intent = new Intent(activity, MainActivity.class);
//			startActivity(intent);
//
//			finish();
//		}

		ViewPager mViewPager = (ViewPager) findViewById(R.id.viewpager);

		mViewPager.setOnPageChangeListener(new OnPageChangeListener() {

			@Override
			public void onPageSelected(int pos) {

				circle.choose(pos);
			}

			@Override
			public void onPageScrolled(int arg0, float arg1, int arg2) {

			}

			@Override
			public void onPageScrollStateChanged(int arg0) {

			}
		});

		mViewPager.setAdapter(new MyAdapter(this.getSupportFragmentManager()));
		circle = (MyCircleView) findViewById(R.id.circle);
		// circle.setCount(mViewPager.getChildCount());
		circle.setCount(mViewPager.getAdapter().getCount());
	}

	private class MyAdapter extends FragmentPagerAdapter {

		private int[] imgRes = { R.drawable.welcome1, R.drawable.welcome2, R.drawable.welcome3 };

		public MyAdapter(FragmentManager fm) {
			super(fm);
		}

		@Override
		public Fragment getItem(int pos) {

			final int position = pos;
			Fragment f = new Fragment() {
				@Override
				public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

					View view = null;

					if (position == getCount() - 1) {
						view = inflater.inflate(R.layout.welcome_fragment_button, null);
						Button btn = (Button) view.findViewById(R.id.welcome_button);

						btn.setOnClickListener(new OnClickListener() {

							@Override
							public void onClick(View v) {

								Intent intent = new Intent(activity, MainActivity.class);
								startActivity(intent);

								finish();
							}
						});

					} else {
						view = inflater.inflate(R.layout.welcome_fragment, null);
						ImageView image = (ImageView) view.findViewById(R.id.iamgeView);
						image.setImageResource(imgRes[position]);
					}

					return view;
				}

			};

			return f;
		}

		@Override
		public int getCount() {

			return Constants.PAGE_COUNT;
		}

	}

}

需要的布局文件welcome_main.xml：

需要的布局文件welcome_fragment.xml：

需要的布局文件welcome_fragment_button.xml：