Pager-优快云博客

本文介绍了一个简单的分页器类的实现，并通过实例演示了如何使用该分页器进行页面跳转、获取当前页记录等功能。代码示例中包含了初始化分页器、获取指定页码的数据、获取上一页和下一页数据等操作。
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import java.util.ArrayList;
import java.util.List;
public class Pager {
	public int currentPage = 0;
	private int nextPage;
	private int previousPage;
	private int fristPage;
	public int lastPage;
	private int pageSize = 10;
	private int record_cnt = 67;
	public List<String> currentRecords;
	public List<String> allRecords;

	public Pager(List<String> _allRecords, int _pageSize) {
		this.pageSize = _pageSize;
		allRecords = _allRecords;
		record_cnt = allRecords.size();
		lastPage = this.record_cnt / this.pageSize + 1;
	}

	public int getCurrentPage() {
		return currentPage;
	}

	private int getNextPageNum() {
		if (currentPage < lastPage) {
			nextPage = currentPage + 1;
		} else {
			nextPage = lastPage;
		}
		return nextPage;
	}

	public List<String> getJumpPageRecords(int jumpPage) {
		if (jumpPage >= this.lastPage) {
			return this.getLastPageRecords();
		} else if (jumpPage <= this.fristPage) {
			return this.getFirstPageRecords();
		} else {
			this.currentRecords = new ArrayList<String>();
			for (int i = (jumpPage - 1) * pageSize; i < jumpPage * pageSize; i++) {
				this.currentRecords.add(this.allRecords.get(i));
			}
			this.currentPage = jumpPage;
			return currentRecords;
		}

	}

	public List<String> getNextPageRecords() {
		getNextPageNum();
		if (this.currentPage == lastPage) {
			System.out.println("Already was the last page!!!");
			return null;
		}
		if (nextPage == this.lastPage) {
			return this.getLastPageRecords();
		} else {
			this.currentRecords = new ArrayList<String>();
			for (int i = currentPage * pageSize; i < nextPage * pageSize; i++) {
				this.currentRecords.add(this.allRecords.get(i));
			}
			currentPage = nextPage;
			return currentRecords;
		}

	}

	public List<String> getPreviousPageRecords() {
		this.getPreviousPage();
		if (this.currentPage == 1) {
			System.out.println("Already was the first page!!!");
			return null;
		}
		if (previousPage == 1) {
			return this.getFirstPageRecords();
		} else {
			this.currentRecords = new ArrayList<String>();
			for (int i = (previousPage - 1) * pageSize; i < previousPage
					* pageSize; i++) {
				this.currentRecords.add(this.allRecords.get(i));
			}
			currentPage = previousPage;
			return currentRecords;
		}
	}

	public List<String> getFirstPageRecords() {
		if (lastPage == 1) {
			return this.allRecords;
		} else {
			this.currentRecords = new ArrayList<String>();
			for (int i = 0; i < this.pageSize; i++) {
				this.currentRecords.add(allRecords.get(i));
			}
			this.currentPage = 1;
			return currentRecords;
		}
	}

	public List<String> getLastPageRecords() {
		if (lastPage == 1) {
			return this.allRecords;
		} else {
			this.currentRecords = new ArrayList<String>();
			for (int i = (lastPage - 1) * pageSize; i < this.record_cnt; i++) {
				this.currentRecords.add(allRecords.get(i));
			}
			this.currentPage = lastPage;
			return currentRecords;
		}
	}

	private int getPreviousPage() {
		if (this.currentPage > 1) {
			previousPage = currentPage - 1;
		} else {
			previousPage = 1;
		}
		return previousPage;
	}

	public int getFristPage() {
		fristPage = 0;
		return fristPage;
	}

	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

	// public List<String>
	public static void main(String[] args) {
		List<String> pageRecords = new ArrayList<String>();
		for (int i = 1; i <= 59; i++) {
			pageRecords.add("-+-" + i + "---");
		}
		Pager p = new Pager(pageRecords, 5);
		System.out.println("all: " + p.lastPage);
		List<String> r = p.getJumpPageRecords(2);
		if (r != null) {
			for (String a : r) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}

		List<String> r2 = p.getNextPageRecords();
		if (r2 != null) {
			for (String a : r2) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}

		List<String> r3 = p.getNextPageRecords();
		if (r3 != null) {
			for (String a : r3) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}

		List<String> r4 = p.getPreviousPageRecords();
		if (r4 != null) {
			for (String a : r4) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}

		List<String> r5 = p.getFirstPageRecords();
		if (r5 != null) {
			for (String a : r5) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}
		List<String> r6 = p.getLastPageRecords();
		if (r6 != null) {
			for (String a : r6) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}

		List<String> r7 = p.getNextPageRecords();
		if (r7 != null) {
			for (String a : r7) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}
		List<String> r8 = p.getFirstPageRecords();
		if (r8 != null) {
			for (String a : r8) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}
		List<String> r9 = p.getPreviousPageRecords();
		if (r9 != null) {
			for (String a : r9) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}
		for (int i = 0; i < 17; i++) {
			List<String> r12 = p.getNextPageRecords();
			if (r12 != null) {
				for (String a : r12) {
					System.out.print(a + " | ");
				}
				System.out.println();
				System.out.println("--------current page is :" + p.currentPage
						+ " --------");
			}
		}
		for (int i = 0; i < 12; i++) {
			List<String> r12 = p.getPreviousPageRecords();
			if (r12 != null) {
				for (String a : r12) {
					System.out.print(a + " | ");
				}
				System.out.println();
				System.out.println("--------current page is :" + p.currentPage
						+ " --------");
			}
		}
		List<String> r11 = p.getJumpPageRecords(9);
		if (r11 != null) {
			for (String a : r11) {
				System.out.print(a + " | ");
			}
			System.out.println();
			System.out.println("--------current page is :" + p.currentPage
					+ " --------");
		}
		for (int i = 0; i < 19; i++) {
			List<String> r12 = p.getPreviousPageRecords();
			if (r12 != null) {
				for (String a : r12) {
					System.out.print(a + " | ");
				}
				System.out.println();
				System.out.println("--------current page is :" + p.currentPage
						+ " --------");
			}
		}
	}
}