接上一篇，接下来我们看看android\vendor\qcom\opensource\fm\fmapp2\src\com\caf\fmradio\PresetList.java

定义一个List列表List<PresetStation>mPresetList = new ArrayList<PresetStation>();

同步电台数量

public synchronized int getStationCount(){
        return mPresetList.size();
    }

获得电台名字

 public synchronized String getStationName(int stationNum){
        String name = "";
        if (mPresetList.size() > stationNum){
            name = mPresetList.get(stationNum).getName();
        }
        return name;
    }

获取电台频率

public synchronized int getStationFrequency(int stationNum){
        int frequency = 102100;
        if (mPresetList.size() > stationNum){
            frequency = mPresetList.get(stationNum).getFrequency();
        }
        return frequency;
    }

设置电台频率

public synchronized void setStationFrequency(int stationNum, int frequency){
        PresetStation mStation = mPresetList.get(stationNum);
        mStation.setFrequency(frequency);
    }

设置电台名字

public synchronized void setStationName(int stationNum, String name){
        PresetStation mStation = mPresetList.get(stationNum);
        mStation.setName(name);
    }

通过ID得到电台

public synchronized PresetStation getStationFromIndex(int index){
        int totalPresets = mPresetList.size();
        PresetStation station = null;
        if (index < totalPresets) {
            station = mPresetList.get(index);
        }
        return station;
    }

通过频率得到电台

public synchronized PresetStation getStationFromFrequency(int frequency){
        int totalPresets = mPresetList.size();
        for (int presetNum = 0; presetNum < totalPresets; presetNum++ ) {
            PresetStation station = mPresetList.get(presetNum);
            if (station != null) {
                if(frequency == station.getFrequency()) {
                    return station;
                }
            }
        }
        return null;
    }

添加电台名字和频率

public synchronized PresetStation addStation(String name, int freq){
        PresetStation addStation = new PresetStation(name, freq);
        if(addStation != null) {
            mPresetList.add(addStation);
        }
        return addStation;
    }

添加电台

public synchronized PresetStation addStation(PresetStation station){
        PresetStation addStation = null;
        if(station != null) {
            addStation = new PresetStation (station);
            mPresetList.add(addStation);
        }
        return addStation;
    }

删除电台

 public synchronized void removeStation(int index){
       int totalPresets = mPresetList.size();
       if((index >= 0) && (index < totalPresets))
       {
          mPresetList.remove(index);
       }
    }

清除调频列表

public synchronized void clear(){
        mPresetList.clear();
    }

/ *如果用户选择一个新电台在这个列表中,将调用这个函数来更新列表。

* /

public synchronized boolean setSelectedStation(PresetStation selectStation){
        int totalPresets = mPresetList.size();
        if (selectStation != null) {
            for (int presetNum = 0; presetNum < totalPresets; presetNum++ ) {
                PresetStation station = mPresetList.get(presetNum);
                if (station != null) {
                    if(selectStation.getFrequency() == station.getFrequency()) {
                        if(selectStation.getName().equalsIgnoreCase(station.getName())) {
                            mCurrentStation = presetNum;
                            return true;
                        }
                    }
                }
            }
        }
        return false;
    }

/ *检查是否有相同电台存在在列表中

* /

public synchronized boolean sameStationExists(PresetStation compareStation){
        int totalPresets = mPresetList.size();
        if (compareStation != null) {
            for (int presetNum = 0; presetNum < totalPresets; presetNum++ ) {
                PresetStation station = mPresetList.get(presetNum);
                if (station != null) {
                    if(compareStation.getFrequency() == station.getFrequency()) {
                        return true;
                    }
                }
            }
        }
        return false;
    }

/ *如果用户在这个列表中选择一个新电台,将调用这个例程

*更新列表。

* /

public synchronized boolean setSelectedStation(int stationIndex){
        boolean foundStation = false;
        int totalPresets = mPresetList.size();
        if (stationIndex < totalPresets) {
            mCurrentStation = stationIndex;
            foundStation = true;
        }
        return foundStation;
    }

选择电台

<pre name="code" class="java">public synchronized void selectStation(PresetStation selectStation){
        int totalPresets = mPresetList.size();
        if (selectStation != null) {
            for (int presetNum = 0; presetNum < totalPresets; presetNum++ ) {
                PresetStation station = mPresetList.get(presetNum);
                if (station != null) {
                    if(selectStation.getFrequency() == station.getFrequency()) {
                        mCurrentStation    = presetNum;
                        return;
                    }
                }
            }
        }
    }

获取选择的站

public synchronized PresetStation getSelectedStation(){
        int totalPresets = mPresetList.size();
        PresetStation station = null;
        if (mCurrentStation < totalPresets) {
            station = mPresetList.get(mCurrentStation);
        }
        return station;
    }

选择下一个电台

public synchronized PresetStation selectNextStation(){
        int totalPresets = mPresetList.size();
        PresetStation station = null;
        if(totalPresets > 0) {
            mCurrentStation ++;
            if ( (mCurrentStation) >= totalPresets) {
                mCurrentStation =0;
            }
            station = mPresetList.get(mCurrentStation);
        }
        return station;
    }

 选择上一个电台

 public synchronized PresetStation selectPrevStation(){
        int totalPresets = mPresetList.size();
        PresetStation station = null;
        if(totalPresets > 0) {
            mCurrentStation --;
            if ( mCurrentStation < 0) {
                mCurrentStation = totalPresets-1;
            }
            station = mPresetList.get(mCurrentStation);
        }
        return station;
    }

AndroidFM模块学习之四源码分析（九）